Systems and Methods for Therapeutic Agent Delivery

ABSTRACT

According to some embodiments herein, systems for delivering therapeutic agents and/or methods of using such systems are provided. The systems can be configured to administer solution comprising therapeutic agent to a subject, and can further comprise an ultrasound applicator for applying ultrasound energy to the subject.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a Continuation of U.S. patent applicationSer. No. 15/942,472 filed Mar. 31, 2018 (Allowed); which is a Divisionalof U.S. patent application Ser. No. 14/730,752 filed Jun. 4, 2015 (nowU.S. Pat. No. 9,956,388); which claims the benefit of U.S. ProvisionalAppln. No. 62/007,709 filed Jun. 4, 2014; the entire contents of whichare incorporated herein by reference in their entirety for all purposes.

BACKGROUND

Embodiments herein generally relate to systems for therapeutic agentdelivery and methods of using such systems.

Soft tissue infections are a major global health issue. About 325,000new cases are diagnosed each year. When an inadequate concentration ofantibiotic is used to treat a given infection, antibiotic resistantstrains of bacteria develop that are increasingly difficult to treat.Patients with MRSA cellulitis of the lower extremity, especially thosewith impaired circulation, such as diabetics, are even more difficult totreat with standard delivery methods of antibiotics, such as oral orintravenous administration, because an adequate concentration ofantibiotic cannot be delivered to the target tissues. Consequently over10% of these cases end up in amputation and over $25 billion is spentannually on chronic wounds.

While recent developments in ultrasound driven drug delivery showpromise against such infections and with other treatments (e.g., cancer,colonization, inflammation treatment, etc.), further improvements may bedesired.

SUMMARY

In some aspects, a system for delivering a therapeutic agent to a targettissue in a subject is provided. The system can comprise a containerconfigured to hold a fluid comprising the therapeutic agent. The systemcan comprise at least one of a vacuum source or an inert gas source ingas communication with the container, in which the vacuum source andinert gas source are configured to control a partial pressure ofsolubilized gas in the fluid. The system can comprise a pump in fluidcommunication with the container. The system can comprise a tissueinterface in fluid communication with the pump, in which the pump isconfigured to control a flow of fluid from the container to the tissueinterface. The system can comprise an ultrasound applicator configuredto broadcast energy transcutaneously at a frequency from about 20 kHz toabout 10 MHz and a power density from about 0.1 watts/cm′ to about 10watts/cm². The system can comprise a sensor (e.g., piezoelectric or thelike) configured to detect an acoustic reaction of the subject uponbroadcasting of the energy. In some embodiments, the system furthercomprises a processor in data communication with the sensor and thepump, in which the processor is configured to control the operation ofthe pump in response to data from the sensor. In some embodiments, thesystem further comprises a processor in data communication with thesensor and the ultrasound applicator, wherein the processor isconfigured to control operation of the ultrasound applicator in responseto data from the sensor. In some embodiments, the processor is in datacommunication with the sensor, the pump, and the ultrasound applicator,so that the processor is configured to control operation of the pump andthe ultrasound applicator in response to data from the sensor. In someembodiments, the pump comprises a peristaltic pump. In some embodiments,the container is configured to fluidly connect to a source of fluidcomprising the therapeutic agent. In some embodiments, the systemfurther comprises an ultrasound generator in communication with theultrasound applicator. In some embodiments, the system further comprisesa foot switch configured to control the operation of the ultrasoundgenerator. In some embodiments, the subject is a human. In someembodiments, the subject is a non-human animal. In some embodiments, theultrasound applicator is configured to broadcast energy at a frequencyfrom about 20 kHz to about 5 MHz. In some embodiments, the ultrasoundapplicator is configured to broadcast energy at a power density fromabout 1 watts/cm′ to about 5 watts/cm². In some embodiments, the systemis configured to pulse the broadcast ultrasound energy. In someembodiments, a therapeutically effective concentration of therapeuticagent is delivered to the target tissue.

According to some aspects, a system for delivering a therapeutic agentto a target tissue in a subject is provided. The system can comprise acontainer configured to hold a fluid comprising the therapeutic agent.The system can comprise a cannula administering the fluid to a vicinityof the target tissue, wherein the cannula is in fluid communication withthe container. The system can comprise an ultrasound applicatorconfigured to broadcast energy transcutaneously at a frequency fromabout 20 kHz to about 10 MHz and a power density from about 0.1watts/cm² to about 10 watts/cm². The system can comprise a computingunit for regulating an amount of induced cavitation in fluid afterdelivery of the fluid to the subject. In some embodiments, the systemfurther comprises a sensor configured to detect an acoustic reaction ofthe subject upon broadcasting of the energy. In some embodiments, thesystem further comprises a processor in data communication with thesensor. In some embodiments, the computing unit may control an amount ofcavitation of the fluid in response to data from the sensor. In someembodiments, the computing unit may control a pump in response to datafrom the sensor, thereby controlling the administration of fluid to thetarget tissue. In some embodiments, the sensor is configured to detect abroad band response and a harmonic response. In some embodiments, theprocessor is configured to perform a fast Fourier transform (FFT) on thedetected acoustic reaction, thereby measuring a broad band response andharmonic response. In some embodiments, the computing unit controls atleast one of the frequency or power of the broadcast energy, therebyregulating an amount of cavitation. In some embodiments, the computingunit controls a vacuum source in gas communication with the fluid. Insome embodiments, the computing unit controls a source of inert gas ingas communication with the fluid. In some embodiments, the cannulacomprises an infuser. In some embodiments, the cannula is coupled with apump configured to control administration of the fluid to the subject.In some embodiments, the pump comprises a peristaltic pump. In someembodiments, the system further comprises a foot pedal configured tocontrol the operation of the ultrasound applicator. In some embodiments,the container is configured to fluidly connect to a source of fluidcomprising the therapeutic agent. In some embodiments, the subject is ahuman. In some embodiments, the subject is a non-human animal. In someembodiments, the ultrasound applicator is configured to broadcast energyat a frequency from about 20 kHz to about 5 MHz. In some embodiments,the ultrasound applicator is configured to broadcast energy at a powerdensity from about 1 watts/cm² to about 5 watts/cm². In someembodiments, the system is configured to pulse the broadcast ultrasoundenergy. In some embodiments, a therapeutically effective concentrationof therapeutic agent is delivered to the target tissue.

According to some aspects, a method of dispersing a therapeutic agent ina target tissue is provided. The method can comprise providing a systemcomprising a container configured to hold a fluid comprising thetherapeutic agent, an ultrasound applicator configured to broadcastenergy transcutaneously at a frequency from about 2 kHz to about 10 MHzand a power density from about 0.1 watts/cm² to about 10 watts/cm², anda tissue interface in fluid communication with the container. The methodcan comprise contacting an area at or near the target tissue in thesubject with a tissue interface of the system, in which the subject isin need of dispersal of a therapeutic agent in a target tissue. Themethod can comprise administering a solution comprising the therapeuticagent to the subject via the tissue interface. The method can compriseapplying ultrasound energy at or near the area. The method can compriseautomatically adjusting at least one of (a) a frequency of theultrasound energy; (b) a power of the ultrasound energy; or (c) a rateof administration of the solution comprising the therapeutic agent inresponse to acoustic feedback from application of the ultrasound energy.In some embodiments, the method further comprises pulsing of theultrasound energy in response to acoustic feedback from application ofthe ultrasound energy. In some embodiments, the method further comprisesproviding a desired partial pressure of inert gas in the solutioncomprising therapeutic agent prior to administering the solution. Insome embodiments, the ultrasound energy is applied transcutaneously. Insome embodiments, the concentration delivered to the target tissue istherapeutically effective. In some embodiments, the concentrationdelivered to the target tissue would be toxic if delivered at the sameconcentration as when given systemically to the subject.

In some embodiments, systemic side effects of certain therapeutic agentscan be avoided or prevented. For example, intravenous Vancomycin is theonly route available to treat local tissue infection, which necessarilyrequires high dosages in order to obtain the desired localconcentration. The high dosages, however, are often associated withsevere systemic side effects. With delivery of Vancomycin directly tothe target tissues by this method, extremely small total dosages can beused to achieve the desired therapeutic effect, thus avoiding the sideeffects. For example, when the usual dose, (one gram (1000 mg) ofintravenous Vancomycin) is every twelve hours, a target tissueconcentration of 10 μg/ml. is the goal. With this method, Vancomycin isinjected into the target tissues at a concentration of 10 μg/ml so theinfection can be treated with a total dose of as little as 0.1-0.3 mg ofVancomycin or 1/10,000 the systemic dose. In this embodiment, anytherapeutic agent targeting a local infection or tumor that previouslymust be given intravenously can be given by this method.

In this embodiment, tissues with decreased blood supply such as lowerlimb infections in diabetics or radiated tissue after cancer treatmentcan be treated with local delivery of the therapeutic agent. Forexample, a patient with a chest wall recurrence of breast cancer in aradiated field typically cannot be given enough chemotherapyintravenously in order to treat the tumor. Using methods and systemsdisclosed herein, the chemotherapeutic agent can be delivered at ameasured concentration directly to the tumor without systemic toxicity.

In some embodiments, a system for ultrasonic delivery of a therapeuticagent may be provided. The system may include an ultrasound transducerconfigured to deliver ultrasound energy toward an injected solution withthe therapeutic agent dissolved therein to disperse the therapeuticagent into interstitial space of the target tissue. A sensor may beconfigured to monitor an acoustic response of the target tissuegenerated in response to ultrasound delivered by the ultrasoundtransducer. A controller (computing unit or the like) may be coupledwith the sensor and the ultrasound transducer. The controller may beconfigured to monitor the dispersal of the injected solution with thetherapeutic agent dissolved therein based on the acoustic response ofthe target tissue monitored by the sensor. The controller may be furtherconfigured to adjust the ultrasound delivery depending on the monitoredacoustic response of the target tissue.

The sensor may be further configured to measure a baseline acousticresponse from the target tissue. The controller may be configured toidentify an end point for the ultrasound delivery by comparing themonitored acoustic response of the target tissue to the measuredbaseline acoustic response of the target tissue. The controller mayidentify the end point for the ultrasound delivery when the monitoredacoustic response of the target tissue returns to within a predeterminedthreshold of the measured baseline acoustic response of the targettissue.

The controller may be further configured to adjust the ultrasounddelivery by automatically ceasing delivery of the ultrasound by theultrasound transducer when the controller identifies an end point forthe ultrasound delivery. The controller may be further configured tooutput a user alert to signal adjustments to the ultrasound delivery.The user alert may be associated with an end point of the ultrasounddelivery. The sensor may be configured to monitor a harmonic,subharmonic, and/or broad band response of the target tissue generatedin response to the applied ultrasound. The sensor may be configured tomonitor a harmonic, subharmonic, and/or broad band response of theinjected solution generated in response to the applied ultrasound. Thesensor may be configured to monitor a harmonic, subharmonic, and/orbroad band response of an interaction between the injected solution andthe target tissue generated in response to the applied ultrasound. Thecontroller may be configured to apply a Fast Fourier Transform to themonitored acoustic response of the target tissue to the appliedultrasound. The ultrasound transducer may be configured to deliverultrasound at an applied frequency and wherein the sensor is configuredto monitor target tissue acoustic responses at frequencies other thanthe applied frequency. In some embodiments, the controller may beconfigured to apply a filter to block an input frequency.

The sensor may be configured to monitor a second harmonic response ofthe target tissue. The sensor may be configured to monitor an acousticresponse of the injected solution generated in response to the appliedultrasound. A majority of the acoustic response of the injected solutionmay be due to a concentration of dissolved gas within the injectedsolution. In some embodiments, the controller may be configured toadjust the ultrasound delivery without using an acoustic response ofinjected gas filled drug carriers and without using an acoustic responseof contrast agent that is made of gas filled capsules.

A user input may be provided. The user input may be configured toreceive a user inputted volume of injected solution, a user inputteddepth of target tissue, and/or a user inputted area of target tissue. Atemperature sensor may be coupled with the ultrasound transducer tomonitor a temperature of a face of the ultrasound transducer. Thecontroller may be coupled with the temperature sensor and configured toprevent or cease ultrasound delivery when the temperature of the face ofthe ultrasound transducer exceeds a safety threshold. The controller maybe further configured to output a temperature safety warning in a mannerperceptible to the user.

In further aspects of the present invention, a method of monitoring alevel of dispersal of a therapeutic agent into a target tissue may beprovided. The method may include energizing an ultrasound transducer todeliver ultrasound energy toward a bolus of injected solution includingthe therapeutic agent dissolved therein to disperse the bolus ofinjected solution with the therapeutic agent into interstitial space ofthe target tissue. The dispersal may atomize the therapeutic in thetarget tissue. The dispersal of the bolus of injected solution with thetherapeutic agent into the interstitial space of the target tissue maybe monitored by monitoring an acoustic response of the target tissue orthe injected solution to the applied ultrasound during the ultrasoundapplication. The method may further include adjusting the ultrasounddelivery based on the monitored acoustic response of the target tissueor the injected solution to the applied ultrasound.

The method may further include measuring a baseline acoustic responsefrom the target tissue. The baseline acoustic response of the targettissue may be associated with the acoustic response of the target tissueprior to injection of the solution. An end point for the ultrasounddelivery may be identified by comparing the monitored acoustic responseof the target tissue to the measured baseline acoustic response of thetarget tissue. Optionally, the monitored acoustic response of the targettissue may be compared to the measured baseline acoustic response of thetarget tissue by determining when the monitored acoustic response of thetarget tissue returns to within a predetermined threshold of themeasured baseline acoustic response of the target tissue. The acousticresponse of the target tissue or the injected solution may be monitoredby monitoring a harmonic, subharmonic, and/or broad band response of thetarget tissue or the injected solution to the applied ultrasound. Themethod may further include monitoring a harmonic, subharmonic, and/orbroad band response of an interaction between the injected solution andthe target tissue. A Fast Fourier Transform may be applied to themonitored acoustic response of the target tissue or the injectedsolution to the applied ultrasound. The ultrasound transducer maydeliver ultrasound at an applied frequency and the acoustic response ofthe target tissue may be monitored by monitoring target tissue acousticresponses at frequencies other than the applied frequency. In someembodiments, a second harmonic response from the target tissue or theinjected solution is monitored.

Optionally, an end point of the ultrasound delivery may be identifiedwithout using an acoustic response of injected gas filled drug carriersor an acoustic response of an injected contrast agent of gas filledcapsules. In some embodiments, a temperature of a face of the ultrasoundtransducer may be monitored, and ultrasound delivery may be prevented orceased/terminated when the temperature of the face of the ultrasoundtransducer exceeds a safety threshold and outputting a temperaturesafety warning in a manner perceptible to the user.

In further aspects, a system for ultrasonic delivery of a therapeuticagent may be provided. The system may include an ultrasound transducerconfigured to deliver ultrasound energy at an applied frequency towardan injected solution with the therapeutic agent and a concentration ofgas dissolved therein to disperse the therapeutic agent intointerstitial space of the target tissue. A sensor may be provided thatis configured to monitor an acoustic response of the concentration ofgas dissolved in the injected solution at frequencies other than theapplied frequency—the acoustic response of the dissolved gas may begenerated in response to ultrasound delivered by the ultrasoundtransducer. A controller may be coupled with the sensor and theultrasound transducer. The controller may be configured to monitor thedispersal of the injected solution with the therapeutic agent dissolvedtherein based on the acoustic response of the gas dissolved in theinjected solution monitored by the sensor. The controller may be furtherconfigured to adjust the ultrasound delivery depending on the monitoredacoustic response of the gas dissolved in the injected solution.

In some embodiments, the sensor may be further configured to monitor anacoustic response of the target tissue generated in response to theapplied ultrasound and an acoustic response of an interaction betweenthe injected solution and the target tissue generated in response to theapplied ultrasound. The controller may be configured to identify an endpoint for the ultrasound delivery depending on the monitored acousticresponse of the gas dissolved in the injected solution, the acousticresponse of the target tissue, and the acoustic response of theinteraction between the injected solution and the target tissue.Optionally, the controller may be configured to identify the end pointfor the ultrasound delivery by comparing a baseline target tissueacoustic response with the monitored acoustic response of the gasdissolved in the injected solution, the acoustic response of the targettissue, and/or the acoustic response of the interaction between theinjected solution and the target tissue. In some embodiments, thecontroller may be configured to automatically cease the application ofultrasound upon the identification of the end point for the ultrasounddelivery.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram illustrating a therapeutic agent deliverysystem in accordance with some embodiments herein.

FIGS. 2A-2B illustrate an exemplary ultrasound delivery deviceconfigured to monitor an acoustic reaction according to some embodimentsof the present invention.

FIG. 3 illustrates an exemplary method of monitoring a temperature of anultrasound applicator face according to some embodiments.

FIG. 4 illustrates an exemplary method of calculating ultrasounddelivery duration according to some embodiments of the presentinvention.

FIG. 5 illustrates an exemplary method of monitoring the progress ofultrasound drug dispersal according to some embodiments of the presentinvention.

FIGS. 6A-6C illustrate an acoustic reaction of water under variousconditions.

DETAILED DESCRIPTION

According to some embodiments herein, therapeutic agent delivery systemsand methods of using such systems are provided. In some subjects, atarget tissue in need of a therapeutic agent can have limited access toblood supply. Systems and methods according to some embodiments hereincan be configured for administering a solution comprising therapeuticagent to a subject and applying ultrasound energy during and/or afteradministration in order to efficiently disperse the therapeutic agent inthe target tissue, even if the target tissue has low blood supply.Without being limited by any theory, it is contemplated that thedispersion of therapeutic agent can be a function of the amount ofultrasound energy-induced cavitation in solution or microstreaming ofthe solution. In some embodiments, the system regulates the partialpressure of gas in solution comprising the therapeutic agent, so as toachieve a desired amount and/or strength of cavitation uponadministration. Accordingly, in some embodiments, a solution comprisingtherapeutic agent and a known partial pressure of inert gas isadministered at or near a target tissue. In some embodiments, the systemcomprises a feedback sensor to dynamically control the administration oftherapeutic agent and/or ultrasound energy in response to cavitation ormicrostreaming in the solution in the subject. Cavitation and/ormicrostreaming can be measured by detecting acoustic signals from thesubject across a broad range of frequencies. As such, in someembodiments, the system and/or methods can deliver substantially higherconcentrations of therapeutic agent at or near the target tissue thancould be delivered through other routes, such as intravenous, oral, andthe like. Moreover, systems and/or methods in conjunction withembodiments herein can deliver high concentrations of therapeutic agentdirectly to the target tissue, even if these concentrations would betoxic if administered through other routes, for example intravenously.By way of example, as the extremities of some diabetic patients can becharacterized by low blood flow and can be subject to infection, systemsand methods according to some embodiments herein can administerantibiotic agent at or near an infected tissue and apply ultrasoundenergy to disperse the antibiotic agent throughout the infected tissue.The methods and systems described herein may also be beneficial fortreating various types of cancer (e.g., breast cancer, etc.) or otherradiated tissue, venous ulcers, and chronic colonized wounds.

Systems

According to some embodiments herein, a system is provided foradministration of therapeutic agent to a subject. The system cancomprise a container configured to hold a fluid comprising thetherapeutic agent, and an injection or infusion cannula foradministering the fluid to a vicinity of the target tissue. The cannulacan be in fluid communication with the container, and can comprise atissue interface, and optionally a pump as described herein. The systemcan comprise an ultrasound applicator configured to broadcast energy tothe administered fluid at a frequency from about 2 kHz to about 10 MHzand a power density from about 0.1 watts/cm² to about 10 watts/cm². Insome embodiments, cavitation and/or microstreaming is induced in a fluidin the subject. In some embodiments, the system is configured tobroadcast energy transcutaneously. The system can be configured toregulate an amount of cavitation and/or microstreaming induced in thefluid, for example by providing a desired partial pressure (or range ofpartial pressures) of inert gas in the solution comprising thetherapeutic agent, and/or by dynamically adjusting at least one ofultrasound parameters or the rate of administering a solution comprisingthe therapeutic agent. In some embodiments, the system is configured toadjust ultrasound parameters and/or administration of solutioncomprising therapeutic agent in response to acoustic feedback from thesubject. These embodiments and others are discussed in more detailherein.

FIG. 1 is a schematic diagram illustrating a system 100 according tosome embodiments herein. The system 100 can comprise a container 105configured to hold a fluid comprising therapeutic agent. The system 100can further comprise a gas partial pressure controller for controlling apartial pressure of solubilized gas in the fluid. The gas partialpressure controller can comprise one or both of a vacuum 110 and inertgas source 115 in gas communication with solution in the container 105.The system 100 can further comprise a pump 120 in fluid communicationwith the container 105, and a tissue interface 130 in fluidcommunication with the pump 120, so that the pump 120 can directsolution from the container 105 to the tissue interface 130 for optionaldelivery to a subject. The system 100 can comprise an ultrasoundapplicator 140. In some embodiments, the ultrasound applicator 140 isconfigured to broadcast ultrasonic energy transcutaneously to a subject.Optionally, the system 100 can comprise a sensor 150 configured todetect an acoustic reaction of the subject upon broadcasting of theultrasound energy. In some embodiments, the sensor 150 is directlyattached to the ultrasound applicator 140. In some embodiments thesensor 150 is separate from the ultrasound applicator 140. The system100 can comprise a processor 155 in data communication with the sensor150. The system 100 can comprise an ultrasound generator 160 configuredto provide ultrasound energy via the ultrasound applicator 140.Optionally, the system 100 can comprise a controller 170 for controllingthe operation of the ultrasound generator 160 and/or ultrasoundapplicator 140. In some embodiments, the system 100 comprises a sourceof therapeutic agent 180 in fluid communication with the container 105.In some embodiments, the system 100 comprises a pressure gauge 190configured to monitor pressure in the container 105. Optionally, thesystem 100 may include a temperature sensor for monitoring a temperatureof a face of the ultrasound applicator 140. The temperature sensor mayprovide temperature feedback to the system 100 indicating when the faceof the ultrasound applicator 140 is above a safety threshold. Inresponse to the measured temperature exceeding the safety threshold, thesystem 100 may adjust ultrasound delivery (e.g., frequency or power),terminate the delivery of ultrasound and/or prevent the application ofultrasound and may also output a warning or alert to the user to avoidcontacting a patient with the ultrasound applicator 170. The alert maybe a visual, audio, and/or haptic alert. The alert may be generated atthe ultrasound applicator 170 or by another portion of the system (e.g.,ultrasound generator).

In some embodiments, the system comprises a single module, for example amodule comprising the container 105, processor 155, pump 120, andultrasound generator 160 with a handheld ultrasound applicator 140attachment connected thereto. In some embodiments, the system comprisesa container 105 in a first module, and the ultrasound generator 160 in asecond module, with the processor 155 configured to control the pump 120and also the ultrasound generator 160 and/or applicator 140.

Tissue Interfaces

A variety of tissue interfaces can be used in accordance withembodiments herein, for example cannulas (for example blunt-tippedinfusion cannula), catheters, needles, and the like. A tissue interfacecan administer solution comprising therapeutic agent directly to atarget tissue, or near a target tissue. In some embodiments, the tissueinterface is configured for administration of the solution comprisingtherapeutic agent directly to the target tissue. In some embodiments,the tissue interface is configured for administration of the solutioncomprising therapeutic agent above the target tissue. In someembodiments, the tissue interface can be configured for administrationof the solution comprising therapeutic agent to a periphery the targettissue. In some embodiments, the tissue interface can be configured foradministration of the solution comprising therapeutic agent within 20centimeters of the target tissue, for example within 20 centimeters, 19,18, 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, or 1centimeters, including ranges between any two of the listed values.

The selection of an appropriate tissue interface can be performed by theskilled artisan, and can depend on a number of factors, for example typeof therapeutic agent, quantity of solution to be delivered, type ofsubject, type of target tissue, and the like. In some embodiments, thetissue interface is configured for subcutaneous delivery of thetherapeutic agent. In some embodiments, the tissue interface isconfigured for delivering the therapeutic agent to a body cavity, forexample an abdominal cavity, intracranial space, or other body cavity.In some embodiments, a sterile tissue interface is provided.

Containers

A variety of containers can be used in accordance with embodimentsherein. In some embodiments, the container is configured to hold asolution comprising therapeutic agent. In some embodiments, thecontainer is rigid, for example a tank or tub. In some embodiments, thecontainer is flexible, for example a bag or pouch. In some embodiments,the container is disposable, for example a single-use container. In someembodiments, the container is reusable. In some embodiments, a singlecontainer can be used for multiple administration cycles. In someembodiments, the container is detachable from the system, for examplefor cleaning and sterilization prior to and/or after an administrationcycle.

For sanitary reasons, and also to minimize waste of therapeutic agents,it can be useful for the container to hold a single dose of therapeuticagent. The actual dose and volume can depend on a number of factors, forexample the type of therapeutic agent, the desired concentration of thetherapeutic agent, the disease or indication, characteristics of thesubject, and the like. Accordingly, in some embodiments, the containeris configured for holding any number of volumes of solution within arange, so that the partial pressure of inert gas can be regulatedtherein. In some embodiments the volume is about 1 cc to about 2000 ccor more, for example about 1 cc to about 1000 cc, about 1 cc to about500 cc, about 1 cc to about 250 cc, about 10 cc to about 2000 cc, about10 cc to about 1000 cc, about 10 cc to about 500 cc, about 10 cc toabout 250 cc, about 100 cc to about 2000 cc, about 100 cc to about 1000cc, about 100 cc to about 500 cc, or about 100 cc to about 250 cc.Exemplary total volumes of the container in accordance with someembodiments herein include, but are not limited to about 1 cc, 3, 5, 10,15, 20, 25, 30, 35, 40, 45, 50, 60, 70, 80, 90, 100, 150, 200, 250, 300,350, 400 450, 500, 550, 600, 650, 700, 750, 800, 850, 900, 950, 1000,1100, 1200, 1300, 1400, 1500, 1600, 1700, 1800, 1900, 2000, 2500, 3000,3500, 4000, 4500, 5000 cc or more, including ranges between any two ofthe listed values.

The container can be in fluid communication with a source of therapeuticagent. In some embodiments, the container is connected directly to asource of therapeutic agent. In some embodiments, an intervening member,for example one or more of tubing, a valve, a filter, or an antechamberare positioned between the container and the source of therapeuticagent. In some embodiments, the valve is configured for manual control.In some embodiments, the valve is configured for automatic control, forexample by a processor as described herein.

The container can be in fluid communication with a tissue interface. Insome embodiments, the container is in fluid communication with a pump,which is in fluid communication with the tissue interface. In someembodiments, additional intervening members are positioned between thecontainer and the tissue interface, for example tubing, pumps, valves,restrictions, heparin, and the like.

In some embodiments, the container is in gas communication with a gaspartial pressure controller for increasing and/or decreasing the partialpressure of inert gas in the solution comprising therapeutic agent.Exemplary gas partial pressure controllers include a source of inert gasand/or a vacuum as described herein. In some embodiments, the containerfurther comprises a solution mixer for mixing inert gas with solution toas to increase the partial pressure of inert gas in the solution.Exemplary solution mixers that can be used in accordance with someembodiments herein include stirrers (for example paddles, stir bars, andthe like), magnetic beads, and agitators (for example rockers or shakerswhich can agitate the contents of the container by turning, rocking, orshaking all or part of the container). In some embodiments, thecontainer is connected directly to a source of inert gas and/or vacuum.In some embodiments, an intervening member, for example one or more oftubing, a valve, or a filter are positioned between the container andthe source of therapeutic agent. In some embodiments, the container isin gas communication with a meter such as a pressure gauge formonitoring the pressure or partial pressure of gas in solution. In someembodiments, gas valves are positioned in gas communication between thecontainer and source or inert gas and/or vacuum for controlling thedelivery of inert gas and/or application of vacuum. In some embodiments,the valve is configured for manual control. In some embodiments, thevalve is configured for automatic control, for example by a processor,so that a particular set point or range of partial pressure of inert gasin the solution can be achieved.

Without being limited by any theory, the temperature of the solutioncomprising therapeutic agent can affect a number of factors, such aspartial pressure of inert gas in solution, solubility of therapeuticagent in solution, or suitability for administration to a subject.Accordingly, in some embodiments, the container comprises a temperaturecontroller for regulating the temperature of the solution in thecontainer. In some embodiments a heater, for example one or more of aheating jacket, heating coil, hot plate, or burner, is provided forregulating the temperature of the container. In some embodiments, acooling system, for example a cooling coil, radiative cooler, or sourceof coolant is provided for regulating the temperature of the container.In some embodiments the system is configured to maintain the solution ator below 37° C., for example at or below 37° C., 34° C., 30° C., 25° C.,or 20° C. In some embodiments the system is configured to maintain thesolution at or above 20° C., for example at or above 20° C., 25° C., 30°C., 34° C., or 37° C. In some embodiments, the system is configured tomaintain the solution at about 5° C. or more, for example, 5° C., 10°C., 15° C., 20° C., 25° C., 26° C., 27° C., 28° C., 29° C., 30° C., 31°C., 32° C., 33° C., 34° C., 35° C., 36° C., 37° C., 38° C., 39° C., 40°C., 45° C., or 50° C., including ranges between any two of the listedvalues.

Therapeutic Agents

A variety of therapeutic agents can be provided in accordance withembodiments herein. Therapeutic agents useful in conjunction with someembodiments herein include, but are not limited to small molecules,organic compounds, proteins, peptides, antibodies, antibody fragments,vaccines, and the like. In some embodiments, the therapeutic agent isprovided as a drug cocktail. As used herein “drug cocktail” refers to acombination of two or more therapeutically effective agents, for exampletwo or more of any of the therapeutic agents described herein. In someembodiments, the drug cocktail comprises two, three, four, five, six,seven, eight, nine, ten, or more different therapeutic agents, includingranges between any two of the listed values. In some embodiments, a drugcocktail further includes additional ingredients, such as apharmaceutically acceptable carrier or excipient, buffer, one or moresugars, and/or salts.

The therapeutic agent can be provided in appropriate form for deliveryto a desired target tissue. By way of example, the systems and methodsdisclosed herein can be useful for distributing a solution comprisingtherapeutic agent in a variety of tissues with limited blood supply.Exemplary tissues include, but are not limited to soft tissues, skin,bone, tendons, muscles, joints, joint capsules, vessels, subcutaneoustissues such as subcutaneous fat, lungs, internal organs, abdominalcavities, abdominal cavity, other body cavities, intracranial space,tissue within the spinal column or cranium, neural tissue, or tumors.

Various cancers can have low access to blood supply, for example a chestwall recurrence of breast cancer in a radiated field with limited bloodsupply. Accordingly, in some embodiments, the tissue comprises cancerouscells, for example a tumor. As such, the therapeutic agent can comprisean anti-cancer agent for example a chemotherapy agent such asdaunorubicin, doxorubicin, epirubicin, idarubicin, pirarubicin,aclarubicin, mitoxantrone, paclitaxel, docetaxel, podophyllotoxin,irinotecan, topotecan, actinomycin, bleomycin, plicamycin, andmitomycin, cyclophosphamide, methotrexate, pemetrexed, a deoxynucleosideanalog (e.g. cytarabine, gemcitabine, decitabine, azacitidine,fludarabine, nelarabine, cladribine, clofarabine or pentostatin), amonoclonal antibody (e.g. an anti-EGFR antibody, an anti-her2 antibody,an anti-her3 antibody, or an anti-VEGF antibody), and the like,including combinations of any of the listed items.

Optionally, the target tissue may comprise brain tissue or cancerousbrain tissue. In some embodiments, a drug may be directly delivered tothe brain tissue for treating a cancer or a neurological disorder (e.g.,Parkinson's disease, Alzheimer's, etc.). For example, in someembodiments a drug may be delivered by convection-enhanced deliverywhich establishes a pressure gradient at the tip of an intraparenchymalmicrocatheter inserted into the brain. The establishment of the pressuregradient by the microcatheter exploits bulk flow through theinterstitial spaces of the brain. However, this bulk flow may be slowand may by itself be insufficient to provide therapeutically effectivedoses throughout the target tissue. Thus, in some embodiments,ultrasound may be applied to increase the rate of dispersion of the drugwithin the brain tissue according to methods and systems disclosedherein. The ultrasound may be delivered transcutaneously or coupled withthe microcatheter (e.g., at a distal end or at a proximal end).Accordingly, in some embodiments, transcutaneous ultrasound into thehead may be provided to disperse therapeutic agents into the tissue. Asegmented or phased array transducer may be used to direct the sound tothe desired region to avoid scattering by the skull. Dispersion at thedesired region may be detected by changes in the acoustic responsereturned from the tissue.

In some embodiments, the tissue is inflamed. In some embodiments, thetherapeutic agent comprises an antiviral agent or antifungal agent. Insome embodiments, the tissue is infected. In some embodiments, thetissue may be colonized by microorganisms and treatment to reduce oreliminate microbial bioburden and biofilm may accelerate healing. Forexample, in some embodiments, the mixed flora and biofilm colonizationmay inhibit healing and may be associated with a chronic inflammatoryresponse. Treatment of the colonization may relieve the chronicinflammation. Accordingly, the therapeutic agent can comprise anantibiotic. The antibiotic is not limited in any way and may be selectedbased on the specific circumstances, such as the type of infectionpresent, for example causal bacteria by culture, tissue type, patientallergies, and the like. In some embodiments, the therapeutic agentcomprises Cefazolin. In some embodiments, the therapeutic agentcomprises Vancomycin. In some embodiments, the therapeutic agentcomprises a cephalosporin antibiotic, for example, 7-ACA, Carbacephem,Cefacetrile, Cefaclor, Cefadroxil, Cefalexin, Cefaloglycin, Cefalonium,Cefalotin, Cefamandole, Cefapirin, Cefatrizine, Cefazaflur, Cefazedone,Cefazolin, Cefbuperazone, Cefcapene, Cefclidine, Cefdaloxime, Cefdinir,Cefditoren, Cefepime, Cefetamet, Cefixime, Cefluprenam, Cefmatilen,Cefmenoxime, Cefmetazole, Cefminox, Cefodizime, Cefonicid, Cefoperazone,Ceforanide, Cefoselis, Cefotaxime, Cefotetan, Cefotiam, Cefovecin,Cefoxitin, Cefozopran, Cefpimizole, Cefpiramide, Cefpirome, Cefpodoxime,Cefprozil, Cefquinome, Cefradine, Cefroxadine, Cefsulodin, Ceftarolinefosamil, Ceftazidime, Cefteram, Ceftezole, Ceftibuten, Ceftiofur,Ceftiolene, Ceftizoxime, Ceftobiprole, Ceftriaxone, Cefuroxime,Cefuzonam, Cephaloridine, Cephalosporin C, Cephamycin, Flomoxef,Latamoxef, or Loracarbef. In some embodiments, at least one of theantibiotics comprises Cipro and/or clinimycin. In some embodiments, theantibiotic comprises a penicillin family antibiotic, for examplepenicillin, amoxicillin, amplicillin, diclxacillin, oxacillin,penicillin V, piperacillin, piperacillin and tazobactum (Zosyn™). Insome embodiments the antibiotic comprises a beta-lactam antibiotic.

In some embodiments the therapeutic agent is provided in solution or ina suspension. In some embodiments, the therapeutic agent is formulatedaccording to conventional pharmaceutical practice as described inRemington's Pharmaceutical Sciences (18th ed, Mack Publishing Company,Easton, Pa., 1990). In some embodiments the therapeutic agent isprovided in injectable form. In some embodiments the therapeutic agentis infusible. In some embodiments, the therapeutic agent is provided ina stable form for storage, for example lyophilized, and reconstitutedprior to use. By way of example, suitable isotonic solutions fordissolving a therapeutic agent may be useful for infusion or injectionin accordance with some embodiments herein, for example, saline orringer's lactate, with the optional addition of epinephrine orxylocaine. Optionally, the tumescent fluid may be a hypotonic orhypertonic fluid.

In some embodiments, the therapeutic agent comprises an excipient.Excipients in accordance with some embodiments herein include but arenot limited to antiadherents, binders, coatings, disintegrants, fillersand diluents, lubricants, glidants, preservatives, and sorbents. In someembodiments, the therapeutic agent comprises one or more activeingredients and one or more excipients. In some embodiments thetherapeutic agent is packaged in a carrier. For example, the therapeuticagent can be packaged in liposomes or vesicles. In some embodiments, thetherapeutic agent is not packaged in any carrier, liposomes, orvesicles. For example, the therapeutic agent can be dissolved orsuspended in solution. Accordingly, in some embodiments, the methodincludes dissolving the therapeutic agent in solution if it is notalready dissolved. In some embodiments, therapeutic agent is contactedwith a solution for administration. In some embodiments, therapeuticagent and salts and/or lyophilized components of a solution to beadministered are contacted with a solvent, for example sterile water orsaline.

Appropriate therapeutic agents or combinations of therapeutic agents canbe selected by the skilled artisan, based on a variety of factors, forexample characteristics of the subject, disease state, diseaseprogression, other medications or therapeutic agents being used by thepatient, allergies, and the like.

Subjects

Systems and methods in accordance with embodiments herein can be usefulfor administration of therapeutic agents to a variety of subjects. Insome embodiments, a system or method as provided herein is configured toadminister therapeutic agent to any of a variety of subjects. In someembodiments, the system or method is configured to administertherapeutic agent to a particular type or category of subject, forexample subjects of a particular species and/or particular clinicalindication.

In some embodiments, the subject is a human. In some embodiments, thesubject is a patient in need of treatment. In some embodiments, thesubject is a non-human animal. In some embodiments, the subject is anon-human mammal, for example a cow, horse, sheep, pig, goat, dog orcat. In some embodiments, the subject is a non-human primate.

In some embodiments, the subject is characterized by at least one tissuehaving limited blood supply that is in need of treatment with atherapeutic agent. In some embodiments, the subject has an infection ina tissue having limited blood supply. By way of example, diabeticsubjects can be characterized by limited blood supply to one or moresites of infection. Accordingly, in some embodiments, the subject isdiabetic. By way of example, some tumors can have low blood supply.Accordingly, in some embodiments, the subject has a tumor, andtherapeutic agent is administered at, near, or above the site of thetumor.

In some embodiments, the subject has a target tissue that is notcharacterized by a low blood supply, but the tissue is in need of atreatment with a therapeutic agent at a concentration that would bedeleterious if delivered systemically. Accordingly, systems and methodsaccording to some embodiments herein can disperse a therapeutic agent(for example antibiotic) in a target tissue regardless of whether thetarget tissue has a low blood supply.

In some embodiments, the subject is at risk of developing a diseasestate, for example an infection. Accordingly, in some embodiments,systems and methods in accordance with some embodiments herein canadminister therapeutic agent prophylactically. In some embodiments, thesystems and/or methods can be used to disperse an antibiotic in a targettissue prior to surgery in order to help prevent infection.

Concentrations and Doses of Therapeutic Agent

It has been observed that when a therapeutic agent is administeredintravenously, the concentration of therapeutic agent in serum is higherthan the concentration in the target tissue, especially if the targettissue has limited blood supply. Without being limited by any theory, itis contemplated that in accordance with some embodiments herein,following administration of therapeutic agent at or near a targettissue, the application of ultrasound energy results in efficientdispersal of the therapeutic agent in the target tissue, and can yieldsubstantially greater concentrations and/or amounts of therapeutic agentin the target tissue than will be yielded by intravenous administration.Accordingly, in some embodiments, the system is configured to disperseall or substantially all of the administered therapeutic agent in thetarget tissue. In some embodiments, immediately following, or within 1-2hours of administration of ultrasound energy, the concentration oftherapeutic agent in the target tissue is at least 10× the concentrationin the serum, for example at least about 10×, 20×, 50×, 100×, 200×,500×, 700×, 1000×, 2000×, 3000×, 4000×, 5000×, or 10,000× or greater,including ranges between any two of the listed values. As such, in someembodiments, at least a therapeutically effective concentration andamount of therapeutic agent is administered to the subject.

A variety of doses and concentrations of therapeutic agent can be usedin conjunction with embodiments herein. Without being limited by anytheory, it is contemplated that systems in accordance with embodimentsherein can deliver therapeutic agents at a target tissue or in thevicinity of the target tissue, and as such can be administered at, near,or above therapeutically-effective concentrations, even if the theseconcentrations would be undesirable or deleterious if administeredthrough other routes. For example, while a particular concentration oftherapeutic agent might be effective when present locally at a targettissue, that same concentration might be toxic or lethal if presentsystemically. Additionally, for some routes of administration (forexample intravenous or oral), the concentration of therapeutic agentrequired to achieve an effective concentration of therapeutic agent inthe target tissue may result in an undesirably high systemicconcentration of the therapeutic agent. Accordingly, systems and methodsin accordance with some embodiments herein can minimize or avoidundesirable effects of high systemic concentrations, while achieving auseful local concentration of therapeutic agent in the target tissue.

In some embodiments, the system or method is configured to administer atherapeutically effective amount of therapeutic agent to the targettissue at 50% or more of a concentration that would be lethal ifadministered systemically, for example at least 50%, 60%, 70%, 80%, 90%,100%, 150%, 200%, 250%, 300%, 350%, 400%, 450%, 500%, 600%, 700%, 800%,900%, 1000%, 1500%, 2000%, 3000%, 4000%, 5000%, 6000%, 7000%, 8000%,9000%, or 10,000% of the concentration that would be lethal if presentsystemically, including ranges between any two of the listed values.

In some embodiments, the system or method is configured to administer atherapeutically effective amount of therapeutic agent to the targettissue a therapeutic agent at a concentration of at least 10× greaterthan the maximum concentration that can be administered intravenously,for example at least 10×, 20×, 50×, 100×, 200×, 500×, 700×, 1000×,2000×, 3000×, 4000×, 5000×, or 10,000× or greater, including rangesbetween any two of the listed values. The skilled artisan willappreciate that the actual maximum concentration of the therapeuticagent can depend on the therapeutic agent and/or subject. For example,the skilled artisan may look to the label of the therapeutic agent todetermine the maximum concentration.

After injection, and prior to ultrasound application, the fluid may bepooled in rivulets within the tissue. These rivulets of therapeuticagent are generally unable to treat an infection because the drug staysonly in these pools. By dispersing the drug using ultrasound, oratomized through the tissue, its surface to volume ratio increases andit comes into contact with many more pathogenic cells. Normally, thebody atomizes the drug by first collecting it into the circulatorysystem and then delivering it molecule by molecule via diffusion to thebody tissue. The circulatory fed dispersion is good at dispersion butdramatically lowers the concentration because the circulatory systemdelivers the drug to the entire body. Accordingly, ultrasonic dispersionof the rivulets or pooled fluid with therapeutic agents may increase thesurface area without dilution by the entire body. In some embodiments,the system or method is configured to administer an therapeutic agent,for example a beta-lactam antibiotic such as Cefazolin, at aconcentration of at least about 1,000 μg/ml subcutaneously, for exampleabout 1,000 μg/ml to about 20,000 μg/ml or more, about 1,000 μg/ml toabout 10,000 μg/ml, about 1,000 μg/ml to about 5,000 μg/ml, about 1,000μg/ml to about 2,000 μg/ml, about 2,000 μg/ml to about 20,000 μg/ml,about 2,000 μg/ml to about 10,000 μg/ml, about 2,000 μg/ml to about5,000 μg/ml, about 5,000 μg/ml to about 20,000 μg/ml, or about 5,000μg/ml to about 10,000 μg/ml. After dispersion by ultrasound delivery,the injected fluid may permeate throughout the target tissue toimpregnate the target tissue with concentrations therapeutic agentsdescribed above.

Administration of Therapeutic Agent

Systems in accordance with embodiments herein can be configured toadminister therapeutic agent from the container directly or indirectlyto a subject. In some embodiments, the container is in fluidcommunication with a tissue interface as described herein. In someembodiments, the system comprises a pump in fluid communication with thecontainer and tissue interface, and configured to control the flow ofsolution from the container and through the tissue interface into thesubject, and thus control the flow of solution comprising therapeuticagent from the system to the subject. In some embodiments, the pump isconfigured for manual control. In some embodiments, the pump isconfigured to administer solution comprising therapeutic agent at adesired rate, which can be set by an operator. In some embodiments, thepump is under the control of a processor. The processor can beconfigured to automatically control the operation of the pump. In someembodiments, the processor comprises an electronic processor. In someembodiments, the processor dynamically controls the rate and/or pressureat which the pump administers solution comprising therapeutic agent, forexample in response to feedback signals from an acoustic sensor asdescribed herein. In some embodiments, the pump adjusts its output inresponse to the sensor in real time. For example, the amount of powerand/or the rate or amount of solution injected may be determined by thesize and depth of the tissue being treated. These tissues can vary ascomparing an ankle with a thigh. In some embodiments, the pump adjustsits output in response to a signal detected by the sensor in less than0.5 seconds after the sensor detects the signal, for example less than0.5, 0.2, 0.1, 0.05, or 0.01 seconds.

The pump can be configured to control the administration rate ofsolution comprising therapeutic agent. In some embodiments, the pump isconfigured to increase or decrease its output so as to administer fluidfrom the container to the subject (via the tissue interface) at adesired flow rate. In some embodiments, the desired flow rate is atleast about 0.5 ml/minute, for example about 0.5 ml/minute, 1, 2, 3, 4,5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23,24, 25, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40,41, 42, 43, 44, 45, 46, 47, 48, 49, or 50 ml/minute, including rangesbetween any two of the listed values. In some embodiments, the desiredflow rate is about 0.5 ml/minute-20 ml/minute, for example about 0.5ml/minute-10 ml/minute, about 0.5 ml/minute-5 ml/minute, about 1ml/minute-20 ml/minute, about 1 ml/minute-10 ml/minute, about 1ml/minute-5 ml/minute, about 5 ml/minute-20 ml/minute, or about 5ml/minute-10 ml/minute.

In some embodiments, the pump comprises a peristaltic pump. In someembodiments, the pump comprises a piston pump.

Microstreaming and Gasses

Without being limited by any theory, it is contemplated thatadministration of ultrasound energy at the site of therapeutic agentadministration in a subject in accordance with some embodiments hereincan efficiently disperse the therapeutic agent to a target tissuethrough microstreaming in liquid in the subject. In some embodiments theultrasound energy can be administered less than 5 minutes aftersubcutaneous injection of the delivery fluid, less than 3 minutes afterinjection of the delivery fluid, or sooner (e.g., within 1 minute ofinjection. Optionally, the ultrasound energy may be appliedsimultaneously with the injection procedure. In some embodiments,amounts of microstreaming can be affected by processes that affectnegative pressure, friction, and/or cavitation. For example, frictionalong a flow path can increase an amount of cavitation, so as to produce“friction cavitation.” Furthermore, without being limited by any theory,it is contemplated that a number of fluid-containing tissues in asubject can comprise a number of interstitial channels, which areaffected non-linearly by a variety of factors, for example negativepressure. It is further contemplated that even if the partial pressureof gas in liquid itself is too weak to induce cavitation, the negativepressure can affect the state of the interstitial channels, and thusindirectly can affect microstreaming. Accordingly, it is contemplatedherein that amounts of microstreaming and/or cavitation (and thusdispersion of therapeutic agent in tissue) can be regulated inaccordance with some embodiments herein by regulating amounts ofcavitation, friction, and/or negative pressure. Without being limited byany theory, it is contemplated that the amount of microstreaming and/orcavitation is proportional to the partial pressure of dissolved gas in aliquid subjected to ultrasound energy. As such, in some embodiments thepartial pressure of dissolved gas in a liquid can be adjusted in orderto tune the amount of microstreaming and/or cavitation that occurs inthe subject, which can in turn affect the amount of dispersal oftherapeutic agent in the tissue. In some cases it may be necessary toincrease the strength of the sound field at which cavitation occur. Thepressure of the dissolved gas may be lowered so as to force thecavitation to take place at higher amplitudes and in turn, be stronger.This may be desirable when the interstitial spaces are more dense orhave less flexibility or permeability. Suppression of cavitation tohigher sound field levels may increase other microstreaming capabilitiesoff the sound field. In some embodiments, inert gas/and or negativepressure is applied to liquid comprising therapeutic agent prior toadministration so as to achieve a desired range of partial pressure ofgas in the liquid and achieve a desired amount of microstreaming and/orcavitation in the subject. In some embodiments, inert gas is applied toliquid comprising therapeutic agent prior to administration so as toachieve a desired amount of microstreaming and/or cavitation in thesubject. In some embodiments, negative pressure is applied to liquidcomprising therapeutic agent prior to administration so as to achieve adesired amount of microstreaming and/or cavitation in the subject. Insome embodiments, a combination of inert gas and negative pressure areapplied to liquid comprising therapeutic agent prior to administrationso as to achieve a desired amount of microstreaming and/or cavitation inthe subject. In some embodiments, the inert gas and negative pressureare applied alternatingly. In some embodiments, the inert gas andnegative pressure are applied alternatingly and sequentially. In someembodiments, the inert gas and negative pressure are appliedsimultaneously. Thus, in some embodiments the delivery of therapeuticagent can be tuned for a desired concentration of therapeutic agent inthe target tissue.

Solution administered to the subject can comprise any of a number ofgasses that can affect the amount of microstreaming in accordance withsome embodiments. In some embodiments, the solution comprises acombination of two or more gasses. Without being limited by any theory,it is contemplated that inert gasses are less likely than reactivegasses to induce side effects upon administration to the subject.Accordingly, in some embodiments, the solution comprises at least oneinert gas. In some embodiments, a mixture of two or more inert gasses isprovided. In some embodiments, the inert gas comprises a group 8Aelement, for example helium, neon, argon, krypton, xenon, or radon. Insome embodiments, the inert gas comprises argon. In some embodiments,the inert gas comprises nitrogen. It is noted that while reference ismade herein to inert gas, it is also possible for solutions inaccordance with some embodiments herein to contain small or traceamounts of other gasses, including non-inert gasses.

Systems in accordance with embodiments herein can be configured forcontrolling the partial pressure of inert gas in the solution comprisingtherapeutic agent. The system can comprise a source of inert gas, forexample a canister. In some embodiments the source of inert gas isdetachable form the system, for example to facilitate attachment of acanister comprising a desired inert gas, or to facilitate replacement ofempty canisters. In some embodiments, the source of inert gas is in gascommunication with a container in the system. In some embodiments, thecontainer is configured to mix the inert gas with solution comprisingtherapeutic agent. In some embodiments, the container is free, or issubstantially free of other gasses, so that a total pressure in thechamber can serve as a proxy for partial pressure of inert gas. In someembodiments, the container is purged of other gasses, for example with avacuum, prior to application of the inert gas.

In some embodiments, the container comprises a meter such as a pressuregauge for monitoring the partial pressure of gas in the solution, sothat a user may apply desired partial pressure of inert gas to thesolution, for example, applying additional inert gas and/or a vacuumuntil a desired partial pressure of inert gas is achieved. For example,in some embodiments, an operator can open a valve positioned between thesource of inert gas and the container, while closing a valve positionedbetween the vacuum and the container (and/or turn off the vacuum), andcan turn on a solution mixer. The operator can continue to add inert gasand mix until the partial pressure of inert gas is raised to a desiredlevel. Optionally, the operator can first use the vacuum to purge thecontainer of other gasses prior to or concurrently with adding inertgas. In some embodiments, the operator can close a valve between thecontainer and the source of inert gas, and can open a valve between thecontainer and the vacuum so as to bleed off inert gas until the partialpressure of inert gas is lowered to a desired level. In someembodiments, the solution is mixed or agitated so as to dissolve theinert gas therein. In some embodiments, the system is configured toautomatically to add or remove gas so as to arrive at a particularpartial pressure of gas in the solution. In some embodiments, thepartial pressure of inert gas is set to a set point, and the system isconfigured to automatically maintain the partial pressure at the setpoint.

In some embodiments, an operator selects a desired partial pressure (orrange of partial pressures), and sets the system to provide the partialpressure of inert gas in the solution in the container at that desiredpartial pressure (or within the desired range). In some embodiments, theoperator can optionally adjust the partial pressure from procedure toprocedure. In some embodiments, the system is configured to place thepartial pressure of the inert gas at 25° C. in the range of about 1 kPato about 500 kPa, for example about 1 kPa to about 400 kPa, about 1 kPato about 300 kPa, about 1 kPa to about 200 kPa, about 1 kPa to about 150kPa, about 1 kPa to about 100 kPa, about 1 kPa to about 70 kPa, about 1kPa to about 50 kPa, about 1 kPa to about 30 kPa, about 1 kPa to about20 kPa, about 1 kPa to about 10 kPa, about 1 kPa to about 5 kPa, about 3kPa to about 500 kPa, about 3 kPa to about 400 kPa, about 3 kPa to about300 kPa, about 3 kPa to about 200 kPa, about 3 kPa to about 150 kPa,about 3 kPa to about 100 kPa, about 3 kPa to about 70 kPa, about 3 kPato about 50 kPa, about 3 kPa to about 30 kPa, about 3 kPa to about 20kPa, about 3 kPa to about 10 kPa, about 3 kPa to about 5 kPa, about 5kPa to about 500 kPa, about 5 kPa to about 400 kPa, about 5 kPa to about300 kPa, about 5 kPa to about 200 kPa, about 5 kPa to about 150 kPa,about 5 kPa to about 100 kPa, about 5 kPa to about 70 kPa, about 5 kPato about 50 kPa, about 5 kPa to about 30 kPa, about 5 kPa to about 20kPa, about 5 kPa to about 10 kPa, about 10 kPa to about 500 kPa, about10 kPa to about 400 kPa, about 10 kPa to about 300 kPa, about 10 kPa toabout 200 kPa, about 10 kPa to about 150 kPa, about 10 kPa to about 100kPa, about 10 kPa to about 70 kPa, about 10 kPa to about 50 kPa, about10 kPa to about 30 kPa, about 10 kPa to about 20 kPa, about 50 kPa toabout 500 kPa, about 50 kPa to about 400 kPa, about 10 kPa to about 300kPa, about 50 kPa to about 200 kPa, about 50 kPa to about 150 kPa, about50 kPa to about 100 kPa, about 100 kPa to about 500 kPa, about 100 kPato about 400 kPa, about 100 kPa to about 300 kPa, about 100 kPa to about200 kPa, or about 100 kPa to about 150 kPa. Exemplary partial pressureof inert gas that can be used in accordance with some embodiments hereininclude, but are not limited to about 1 kPa, 2, 3, 4, 5, 6, 7, 8, 9, 10,11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 25, 30, 35, 40, 45, 50, 55, 60,65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, 120, 125, 130, 135, 140,145, 150, 155, 160, 165, 170, 175, 180, 185, 190, 195, 200, 210, 220,230, 240, 250, 260, 270, 280, 290, 300, 310, 320, 330, 340, 350, 360,370, 380, 390, 400, 410, 420, 30, 440, 450, 460, 470, 480, 490, 500 kPa,or more, including ranges between any two of the listed values. It isnoted that temperature can affect the partial pressure of gas, and assuch, the indicated temperature of 25° C. is provided for a referencepoint only, and does not necessitate that the solution be at 25° C. Itis noted that a solution having a particular partial pressure at 25° C.may have a different partial pressure at a different temperature(assuming other parameters remain constant), but that the particularpartial pressure at 25° C. would still be a characteristic of thesolution. The range of partial pressures at which gas is dissolved intothe injectant fluid may range from 100 Pa to 200 kPA in someembodiments.

Ultrasound Applicators

Ultrasound applicators can be used in accordance with embodimentsherein. In some embodiments, the ultrasound applicator comprises anultrasound transducer. A variety of suitable ultrasound applicators areknown to the skilled artisan, and can be selected based the particularapplication, for example the type of subject, type of therapeutic agent,and/or location of administering the therapeutic agent. Exemplaryultrasound applicators sand generator systems that can be used inconjunction with some embodiments herein include Mettler ElectronicsSonicator™ series ultrasound devices (e.g. Sonicator™ 715, 716, 740,740x), Mettler Electronics Sonicators Plus™ series ultrasound devices(e.g. Sonicator Plus™ 930, 940, 992, and 994), US Pro 2000™ portableultrasound device, Chattanooga Inetlect TransPort™ ultrasound units,SoundCare™ plus ultrasound units, other available ultrasound unitsconfigured for output at about 1 MHz to about 3 MHz or more, andmodifications thereof. In some embodiments, the ultrasound applicatorcomprises a handheld applicator. In some embodiments, the ultrasoundapplicator comprises a wand. In some embodiments, the ultrasoundapplicator comprises a catheter. In some embodiments, the system isconfigured to be compatible with any of a number of ultrasoundapplicators, depending on the desired use. In some embodiments, theultrasound applicator is configured for transcutaneous or transdermalapplication of ultrasound energy. In some embodiments, the ultrasoundapplicator is configured to apply ultrasonic energy directly to thetarget tissue. In some embodiments, the ultrasound applicator isconfigured to apply ultrasonic energy near the target tissue, forexample within 20 cm, 19 cm, 18 cm, 17 cm, 16 cm, 15 cm, 14 cm, 13 cm,12 cm, 11 cm, 10 cm, 9 cm, 8 cm, 7 cm, 6 cm, 5 cm, 4 cm, 3 cm, 2 cm, 1cm, or 0.5 cm of the target tissue, including ranges between any two ofthe listed values.

In some embodiments, the ultrasound applicator is operatively connectedto an ultrasound generator. A variety of ultrasound generators are knownto the skilled artisan, including ultrasound generators of the exemplaryultrasound systems described above and modifications thereof, Anultrasound generator having suitable performance characteristics (forexample suitable power levels and ranges of ultrasound frequency) can beselected by the skilled artisan.

In some embodiments, the ultrasound applicator (alone or in conjunctionwith an ultrasound generator) is configured to deliver ultrasonic energytranscutaneously at a frequency of about 10 kHz to about 10 MHz and apower density of 0.5 to about 20 watts/cm². In some embodiments, theultrasound applicator and/or generator are configured to deliverultrasonic energy transcutaneously at a frequency of about 20 kHz toabout 5 MHz. In some embodiments, the ultrasound applicator and/orgenerator are configured to deliver ultrasonic energy transcutaneouslyat a power density of about 1 watt/cm² to about 10 watts/cm². In someembodiments, the ultrasound applicator and/or generator are configuredto deliver ultrasonic energy transcutaneously at a frequency of about 20kHz to about 5 MHz and a power density of 1 to about 5 watts/cm′, forexample a frequency of about 20 kHz to about 5 MHz and a power densityof about 1 to about 10 watts/cm²; a frequency of about 20 kHz to about 5MHz and a power density of about 2 to about 10 watts/cm²; a frequency ofabout 20 kHz to about 5 MHz and a power density of about 3 to about 10watts/cm²; a frequency of about 20 kHz to about 5 MHz and a powerdensity of about 4 to about 10 watts/cm2; a frequency of about 20 kHz toabout 5 MHz and a power density of about 5 to about 10 watts/cm²; afrequency of about 20 kHz to about 5 MHz and a power density of about 2to about 5 watts/cm²; a frequency of about 20 kHz to about 5 MHz and apower density of about 3 to about 5 watts/cm²; a frequency of about 20kHz to about 5 MHz and a power density of about 4 to about 5 watts/cm²;a frequency of about 20 kHz to about 5 MHz and a power density of about1 to about 4 watts/cm²; a frequency of about 20 kHz to about 5 MHz and apower density of about 1 to about 3 watts/cm²; a frequency of about 20kHz to about 5 MHz and a power density of about 1 to about 2 watts/cm²;a frequency of about 100 kHz to about 5 MHz and a power density of about1 to about 10 watts/cm²; a frequency of about 100 kHz to about 5 MHz anda power density of about 2 to about 10 watts/cm²; a frequency of about100 kHz to about 5 MHz and a power density of about 3 to about 10watts/cm²; a frequency of about 100 kHz to about 5 MHz and a powerdensity of about 4 to about 10 watts/cm2; a frequency of about 100 kHzto about 5 MHz and a power density of about 5 to about 10 watts/cm²; afrequency of about 100 kHz to about 5 MHz and a power density of about 1to about 5 watts/cm²; a frequency of about 100 kHz to about 5 MHz and apower density of about 2 to about 5 watts/cm²; a frequency of about 100kHz to about 5 MHz and a power density of about 3 to about 5 watts/cm²;a frequency of about 100 kHz to about 5 MHz and a power density of about4 to about 5 watts/cm²; a frequency of about 100 kHz to about 5 MHz anda power density of about 1 to about 4 watts/cm²; a frequency of about100 kHz to about 5 MHz and a power density of about 1 to about 3watts/cm²; a frequency of about 100 kHz to about 5 MHz and a powerdensity of about 1 to about 2 watts/cm²; a frequency of about 1 MHz toabout 5 MHz and a power density of about 1 to about 10 watts/cm²; afrequency of about 1 MHz to about 5 MHz and a power density of about 2to about 10 watts/cm²; a frequency of about 1 MHz to about 5 MHz and apower density of about 3 to about 10 watts/cm²; a frequency of about 1MHz to about 5 MHz and a power density of about 4 to about 10 watts/cm2;a frequency of about 1 MHz to about 5 MHz and a power density of about 5to about 10 watts/cm²; a frequency of about 1 MHz to about 5 MHz and apower density of about 1 to about 5 watts/cm²; a frequency of about 1MHz to about 5 MHz and a power density of about 2 to about 5 watts/cm²;a frequency of about 1 MHz to about 5 MHz and a power density of about 3to about 5 watts/cm²; a frequency of about 1 MHz to about 5 MHz and apower density of about 4 to about 5 watts/cm²; a frequency of about 1MHz to about 5 MHz and a power density of about 1 to about 4 watts/cm²;a frequency of about 1 MHz to about 5 MHz and a power density of about 1to about 3 watts/cm²; a frequency of about 1 MHz to about 5 MHz and apower density of about 1 to about 2 watts/cm²; a frequency of about 20kHz to about 2 MHz and a power density of about 1 to about 10 watts/cm²;a frequency of about 20 kHz to about 2 MHz and a power density of about2 to about 10 watts/cm²; a frequency of about 20 kHz to about 2 MHz anda power density of about 3 to about 10 watts/cm²; a frequency of about20 kHz to about 2 MHz and a power density of about 4 to about 10watts/cm2; a frequency of about 20 kHz to about 2 MHz and a powerdensity of about 5 to about 10 watts/cm²; a frequency of about 20 kHz toabout 2 MHz and a power density of about 1 to about 5 watts/cm²; afrequency of about 20 kHz to about 2 MHz and a power density of about 2to about 5 watts/cm²; a frequency of about 20 kHz to about 2 MHz and apower density of about 3 to about 5 watts/cm²; a frequency of about 20kHz to about 2 MHz and a power density of about 4 to about 5 watts/cm²;a frequency of about 20 kHz to about 2 MHz and a power density of about1 to about 4 watts/cm²; a frequency of about 20 kHz to about 2 MHz and apower density of about 1 to about 3 watts/cm²; a frequency of about 20kHz to about 2 MHz and a power density of about 1 to about 2 watts/cm²;a frequency of about 20 kHz to about 1 MHz and a power density of about1 to about 10 watts/cm²; a frequency of about 20 kHz to about 1 MHz anda power density of about 2 to about 10 watts/cm²; a frequency of about20 kHz to about 1 MHz and a power density of about 3 to about 10watts/cm²; a frequency of about 20 kHz to about 1 MHz and a powerdensity of about 4 to about 10 watts/cm2; a frequency of about 20 kHz toabout 1 MHz and a power density of about 5 to about 10 watts/cm²; afrequency of about 20 kHz to about 1 MHz and a power density of about 1to about 5 watts/cm²; a frequency of about 20 kHz to about 1 MHz and apower density of about 1 to about 5 watts/cm²; a frequency of about 20kHz to about 1 MHz and a power density of about 2 to about 5 watts/cm²;a frequency of about 20 kHz to about 1 MHz and a power density of about3 to about 5 watts/cm²; a frequency of about 20 kHz to about 1 MHz and apower density of about 4 to about 5 watts/cm²; a frequency of about 20kHz to about 1 MHz and a power density of about 1 to about 4 watts/cm²;a frequency of about 20 kHz to about 1 MHz and a power density of about1 to about 3 watts/cm²; or a frequency of about 20 kHz to about 1 MHzand a power density of about 1 to about 2 watts/cm². In someembodiments, a smaller diameter transducer may be used which will allowaccess to regions of the foot area. In some embodiments, the ultrasoundapplicator and/or generator are further configured to provide ultrasoundenergy at powers and/or densities outside of the stated ranges.

In some embodiments, the ultrasound applicator and/or ultrasoundgenerator are configured to pulse the ultrasound energy. In someembodiments, a suitable pulse duration and frequency are selected by anoperator. In some embodiments, a pulse of ultrasound energy having aduration of about 0.1 second to about 20 seconds is provided, forexample about 0.1 to about 20 seconds, about 0.1 to about 10 seconds,about 0.1 to about 5 seconds, about 0.1 to about 2 seconds, about 0.1 toabout 1 second, about 0.1 to about 0.5 seconds, about 0.2 to about 20seconds, about 0.2 to about 10 seconds, about 0.2 to about 5 seconds,about 0.2 to about 2 seconds, about 0.2 to about 1 second, about 0.2 toabout 0.5 seconds, about 0.5 to about 20 seconds, about 0.5 to about 10seconds, about 0.5 to about 5 seconds, about 0.5 to about 2 seconds,about 0.5 to about 1 second, about 1 to about 20 seconds, about 1 toabout 10 seconds, about 1 to about 5 seconds, about 1 to about 2seconds, about 2 to about 20 seconds, about 2 to about 10 seconds, about2 to about 5 seconds, about 5 to about 20 seconds, or about 5 to about10 seconds. In some embodiments, the duration between pulses is at leastabout 0.5 seconds, for example, at least about 0.5 seconds, 1, 2, 3, 4,5, 6, 7, 8, 9, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75,80, 85, or 90 seconds, including ranges between any two of the listedvalues. In some embodiments, the ultrasound applicator is configured topulse ultrasound energy for about 0.1 to 20 seconds at a pulse frequencyof about 2-100 pulses per minute, for example about 0.1 to 20 seconds ata pulse frequency of about 2-100 pulses per minute, about 1 to 20seconds at a pulse frequency of about 2-100 pulses per minute, about 0.1to 10 seconds at a pulse frequency of about 2-100 pulses per minute,about 0.1 to 5 seconds at a pulse frequency of about 2-100 pulses perminute, about 1 to 20 seconds at a pulse frequency of about 2-50 pulsesper minute, about 0.1 to 10 seconds at a pulse frequency of about 2-50pulses per minute, about 0.1 to 5 seconds at a pulse frequency of about2-50 pulses per minute, about 1 to 20 seconds at a pulse frequency ofabout 2-10 pulses per minute, about 0.1 to 10 seconds at a pulsefrequency of about 2-10 pulses per minute, or about 0.1 to 5 seconds ata pulse frequency of about 2-10 pulses per minute.

In some embodiments, the ultrasound applicator and/or ultrasoundgenerator are in data communication with a controller for turning theapplication of ultrasound energy on and off. In some embodiments, thecontroller comprises a foot pedal, trigger, button, or dial.

It is noted that for some subjects, relatively high and prolongedultrasound output can induce burning of tissue at or near the site ofultrasound energy administration, or otherwise can induce tissue damage.Accordingly, in some embodiments, the ultrasound duty cycle is chosen tominimize likelihood of burning, and also to minimize power appliedrelative to effective penetration of the therapeutic agent into thetarget tissue.

In some embodiments, the ultrasound applicator and/or ultrasoundgenerator are in communication with a processor. The processor cancontrol the duty cycle of the ultrasound applicator, for example bycontrolling the frequency, energy, and/or pulse parameters of theultrasound energy administered. In some embodiments, the processoradjusts the ultrasound duty cycle in response to feedback from a sensoras described herein. In some embodiments, the processor adjusts theultrasound duty cycle in response to the sensor in real time. In someembodiments, the processor adjusts the ultrasound duty cycle in responseto a signal detected by the sensor in less than 0.5 seconds after thesensor detects the signal, for example less than 0.5, 0.2, 0.1, 0.05, or0.01 seconds. In some embodiments, the processor is selected to providea minimum ultrasound energy and/or frequency so as to effectivelydisperse the therapeutic agent in the target tissue, while minimizing arisk of tissue damage (e.g. burning) due to ultrasound energy. In someembodiments, a power and/or frequency may be gradually increased untilcavitation/microstreaming is detected. At that point, the power and/orfrequency may be held constant until cavitation/microstreaming is nolonger detected. In other embodiments, a power and frequency may be usedthat is known to cause cavitation/microstreaming (e.g., as detected byan increased harmonic response). The response may be monitored duringthe application to determine the extent of dispersion. If a duration ofthe dispersion is shorter than expected, a sound level may be increasedto see if a desired harmonic response is returned. Thereafter, the soundlevel may be held constant until the full dispersion. For example, in acase of cancer or the like, ultrasound may start at 3 W/cm². Noharmonics in the acoustic response may be indicative of a lack ofdispersion. Thereafter, the sound field may be increased and/or afrequency may be increased until a harmonics/subharmonic or broadbandresponse is returned. At that point, the ultrasound may be applied untildispersion is complete.

Sensors

It is contemplated that delivery of therapeutic agent in accordance withsome embodiments herein can be further enhanced by dynamically adjustingdelivery parameters. Without being limited by any theory, it iscontemplated that the amount of microstreaming and/or cavitation can beproportional to the amount of dispersal of therapeutic agent in thetissue. As such, in some embodiments, the amount of microstreamingand/or cavitation is increased so as to increase the amount oftherapeutic agent being dispersed in a tissue. In some embodiments, theamount of microstreaming and/or cavitation is decreased so as todecrease the amount of therapeutic agent being dispersed in a tissue.For example, the ultrasound frequency and/or energy can be adjusted inresponse to the amount of microstreaming and/or cavitation that isoccurring in the subject, for example to maintain a desiredmicrostreaming and/or cavitation or a range of microstreaming and/orcavitation. For example, the rate of delivery of therapeutic agent canbe adjusted in response to the amount of cavitation that is occurring inthe subject. For example, the ultrasound frequency and/or energy and therate of delivery of therapeutic agent from the container can be adjustedin response to the amount of cavitation that is occurring in thesubject.

Accordingly, in some embodiments, the system comprises a sensorconfigured to sense the amount of microstreaming and/or cavitation inthe subject. In some embodiments, the sensor is configured to measurethe acoustic reaction of the subject. Without being limited by anytheory, it is contemplated that even if the ultrasound transduceroutputs ultrasound energy at a particular frequency, a range offrequencies can be receivable from the subject, including both broadband and harmonic and subharmonic frequencies. As such, in someembodiments, the measurement of acoustic reaction includes a broad bandresponse. The broad band and harmonic response of the target tissue, theinjected solution, and an interaction between the target tissue and theinjected solution may be monitored by the sensor.

In some embodiments, the sensor comprises a sound-measuring transducer.In some embodiments, the transducer is configured to detect acousticsignals from a broad band. The measurements from the sound measuringtransducer can then be processed, for example by subjecting the sensedsignals to a Fast Fourier Transform (FFT) algorithm. The FFT-transformedsignals can permit evaluation of the response of the body at a broadrange of frequencies, for example all frequencies or substantially allfrequencies. In some embodiments, the sensor is in data communicationwith a processor, and the processor processes the measurements, forexample by applying the FFT. Optionally the FFT may be combined with afilter that blocks the input frequency. In some embodiments a spectrumanalyzer may be used.

In some embodiments, the sensor is in data communication with aprocessor that controls the amount of induced microstreaming and/orcavitation in response to the acoustic reaction detected by the sensor.In some embodiments, the sensor is in wireless data communication withthe processor. In some embodiments, the sensor is directly or indirectlywired to the processor. In some embodiments the processor is configuredto adjust ultrasound parameters (frequency and/or power) in response tothe amount of microstreaming and/or cavitation detected. For example,the processor can increase ultrasound power and/or frequency to increasethe amount of microstreaming and/or cavitation, or can decrease theultrasound power and/or frequency to decrease the amount ofmicrostreaming and/or cavitation. In some embodiments, a particular setpoint for an amount of microstreaming and/or cavitation is selected byan operator. The set point can be based on a variety of factors, forexample type of therapeutic agent, type of tissue for delivery, size oftissue, and the like. The processor can modulate the ultrasoundparameters in response to the acoustic reaction in the subject so as tomaintain microstreaming and/or cavitation at or near the set point. Insome embodiments, the operator can set a threshold, so thatmicrostreaming and/or cavitation do not fall below a certain threshold,or does not exceed a certain threshold. The threshold may be a point atwhich the broad band sound field and/or the subharmonics/extra harmonicenergy are no longer present in the acoustic response. In someembodiments, the operator can set a range between two thresholds, sothat microstreaming and/or cavitation do not fall below a certainthreshold and does not exceed a certain threshold. In some embodiments,delivery of solution comprising therapeutic agent to the subjectcontinues for a set amount of time at a desired microstreaming and/orcavitation level so as to achieve a therapeutically effectiveconcentration of therapeutic agent in the subject.

In some embodiments, the ultrasound applicator comprises the sensor. Insome embodiments, the sensor is mounted directly on the ultrasoundapplicator. In some embodiments, the sensor is separate from theultrasound applicator, for example, so that the operator can hold theultrasound applicator in one hand and the sensor in the other hand.

For example, FIGS. 2A-2B illustrate an exemplary ultrasound applicator10 including an acoustic sensor 12 integrated therewith according tosome embodiments of the invention. FIG. 2A illustrates ultrasoundapplicator 10 broadcasting ultrasound 14 across the surface 16 of theskin 18 of a patient toward a target tissue 20. In response to thebroadcasted ultrasound 14, the target tissue 20 will emit an acousticsignal. A portion of this signal 22 may reflect back toward theultrasound applicator 10 and the acoustic sensor 12. This acousticresponse 22 may be detected by the acoustic sensor 12. The acousticresponse 22 from the target tissue 20 prior to delivery of fluid mayprovide a baseline target tissue acoustic response that may be latercompared with an acoustic response from the target tissue with the fluiddelivered, as illustrated in FIG. 2B. FIG. 2B shows ultrasoundapplicator 10 broadcasting ultrasound 14 across the surface 16 of skin18 of a patient toward a target tissue 20 and a delivered fluid 24 todisperse the delivered fluid into the target tissue 20. In response tothe broadcasted ultrasound 14, the delivered fluid 24 may create anadditional acoustic response signal. A portion of this signal 26 may bereflected back to sensor 12 and the target tissue 20 may reflect asignal 22 back toward the ultrasound applicator 10 and the acousticsensor 12. The acoustic sensor 12 may detect signal 22 and signal 26 andmay compare the acoustic response of the delivered fluid 24 and thetarget tissue 20 to the baseline acoustic response of the target tissue20 (e.g., measured in FIG. 2A) to monitor a dispersal of the fluid 24.In some embodiments, an ultrasound delivery may be adjusted (e.g.,terminated or the like) based on the fluid 24 dispersal monitoring.While the illustrated ultrasound applicator 10 includes an integratedacoustic sensor 12, it should be understood that the sensor 12 may beseparate from the ultrasound applicator 10. When a separate acousticand/or ultrasound sensor is used, a portion of the acoustic response ofthe tissue and/or injected fluid may be detected at a different locationthan the ultrasound delivery location. For example, the acousticresponse detected may be in a forward direction relative to the acousticapplicator.

Temperature Safety Feature

As discussed above, the system 100 may include a temperature sensor formonitoring a temperature of a face of the ultrasound applicator 140.This may be an advantageous safety feature as the temperature sensor mayprovide temperature feedback to the system 100 and/or to the userindicating when the face of the ultrasound applicator 140 is above asafety threshold. In response to the measured temperature exceeding thesafety threshold, the system 100 may adjust delivery of ultrasound andmay also output a warning or alert to the user. Thus in someembodiments, a temperature safety monitoring method is provided.

FIG. 3 illustrates an exemplary method 200 according to some embodimentsof the present invention. At 202, a temperature of the ultrasoundapplicator face may be measured. At 204, the measured temperature may becompared to a safety threshold temperature. At 206, ultrasound deliverymay be adjusted when the measured temperature is greater than the safetythreshold temperature. At 208, an alert may be outputted to the userthat is indicative of the adjustment in ultrasound delivery.

The temperature of the ultrasound applicator face may be measured by aseparate temperature monitoring system. Alternatively, the temperaturemay be measured by an integrated temperature sensor. The sensor may beone or more of an infrared sensor, a thermocouple, thermistor,resistance temperature sensors, or the like or combinations thereof.

A temperature safety threshold may be preprogrammed into the system ormay be set by a user. In some embodiments, multiple thresholds may beused. Each threshold may be associated with different adjustments to theultrasound delivery and/or alerts to the user. For example, anintermediate threshold may be provided which is associated with an“intermediate caution” alert to the user. A higher threshold may also beused which is associated with an “extreme caution warning” alert to theuser. In some embodiments, a safety threshold may be set between 42-46degrees Celsius, preferably between 43-45 degrees Celsius, and even morepreferably to about 44 degrees Celsius.

As set forth above, adjustments to the ultrasound delivery may be madewhen the measured temperature exceeds a set temperature threshold. Forexample, triggering an “extreme caution warning” may also be associatedwith a termination of the ultrasound delivery or a prevention of theapplication of ultrasound by the ultrasound applicator unit until themeasured temperature of the ultrasound applicator falls below one ormore of the thresholds. In some embodiments, the adjustment may be anadjustment of a power, frequency, or duration of ultrasound delivery.For example, in some embodiments, it may be preferable to decrease apower or frequency of ultrasound delivery when a temperature thresholdis exceeded by a measured temperature. Such a decrease in power orfrequency may allow the ultrasound dispersion to proceed for a longerduration as needed. In other embodiments, it may be desirable toimmediately cease the delivery of ultrasound or to prevent theactivation of the ultrasound transducer to prevent further heating andto reduce the chances of inadvertently injuring the patient when themeasured temperature exceeds a safety threshold temperature.

An alert may be outputted by the system to the user. The alert may beindicative of an adjustment made to the ultrasound delivery. Optionally,the alert may be associated only with a measured temperature exceedingan intermediate threshold, where no adjustments to ultrasound deliveryare made. The alert may be a visual alert, audio alert, and/or a hapticalert or combinations thereof. For example, the alert may be presentedon a display of the system or output through one or more light sources(e.g., red, yellow, green LEDs or the like) on the ultrasound generatoror the ultrasound applicator. Optionally, the alert may include acontinuous sound or a one or a series of discrete beeps. An audio alertmay be a record voice in some embodiments. For example, an audio warningfrom the system may advise the user to avoid contacting the applicatorto the patient. Optionally, the alert may be a haptic vibrationtransmitted to the hand of the user of the system.

Thus, in some embodiments, it may be advantageous to include atemperature monitoring system to monitor a temperature of the ultrasoundapplicator face. This may reduce the possibility of inadvertent injuryto a patient.

Ultrasound Duration Calculation

In some embodiments, it may be beneficial for a treatment system to beable to automatically calculate a duration for ultrasound applicationbased on user inputted treatment parameters. This may provide anadditional safety mechanism that reduces the possibility that a userapplies ultrasound for too long a duration which may inadvertentlyinjure a patient. Accordingly, in some embodiments, methods ofcalculating an ultrasound treatment duration are provided.

FIG. 4 illustrates an exemplary method 300 according to someembodiments. At step 302, user inputted treatment parameters arereceived. At step 304, an ultrasound treatment duration is calculatedbased on the received user input. At step 306, the ultrasound transducermay be energized to deliver ultrasound toward the treatment area. Atstep 308, the ultrasound delivery may be terminated when the ultrasoundis applied for the calculated treatment duration.

In some embodiments, a user interface may be provided with the treatmentsystem. The user interface may allow a user to input parameters for thetreatment such that the system may thereafter calculate a preferredduration for the ultrasound driven drug dispersion. For example, in someembodiments, a user interface may be provided for accepting a userinputted volume of fluid that is to be injected or infused into thepatient. Based on the volume of fluid, the treatment system maycalculate a duration for applying the ultrasound from the ultrasoundapplicator. In some embodiments, a treatment volume may be inputted bythe user or parameters related to the treatment volume (e.g., treatmentarea and treatment depth). The system may then calculate the ultrasonicduration based on treatment volume. In some embodiments, the user mayalso input the desired power and frequency for the applied ultrasoundand the calculated duration may be adjusted based on the inputted powerand frequency. In some embodiments the ultrasound duration calculationmay be performed using a preset power and frequency. Optionally, thesystem may calculate a range of durations with a range of powers and arange of frequencies. In some embodiments, the shortest duration out ofthe calculated ranges may be selected as an additional safety mechanism.In some embodiments, a diagnostic ultrasound component may be providedeither separate or combined with the treatment applicator. Thediagnostic ultrasound may be configured to map the depth of targettissue and the target tissue area, both before, during, and/or afterinjection of solution and during dispersion of the therapeutic agent. Insome embodiments the treatment length and power output of the ultrasounddispersion applicator may be monitored by and adjusted in real timebased upon the analysis of the tissue based upon the diagnosticultrasonic array.

Thereafter, ultrasound may be applied toward the target tissue. Theultrasound may interact with a delivered fluid (e.g., via injection,infusion or the like) to disperse the fluid into the tissue of thepatient. The system may monitor a duration of ultrasound delivery andmay automatically cease the ultrasound delivery when the ultrasound hasbeen delivered for the calculated duration.

Ultrasound Dispersal Monitoring

In further embodiments, methods of monitoring ultrasound dispersal areprovided. FIG. 5 illustrates an exemplary method 400 for monitoringdispersal of an agent into the target tissue using ultrasound. At step401, one or more user inputted parameters may be received for ultrasounddelivery and an acoustic response filter may be modified based on theone or more user inputted parameters. At step 402, a baseline acousticresponse from the target tissue may be measured. At step 403, afterdelivery of the fluid, ultrasound may be delivered toward the targettissue to disperse the delivered fluid. At step 404, acoustic responsechanges may be monitored during the delivery of ultrasound to dispersethe fluid into the target tissue. At step 406, adjustments to theultrasound parameters may be made based on the monitored acousticresponse changes. At step 408, an output to the user may be providedthat is indicative of the adjustment to the ultrasound parameters.

Optionally, a user may input one or more parameters for ultrasounddelivery 401 (e.g., power, frequency, etc.) as described above. Whenmonitoring for baseline tissue acoustic responses and acoustic responsesindicative of microstreaming and/or cavitation, it may be beneficial toinclude a signal filter. The signal filter may be configured to filtersome frequencies from a return signal based on the user inputtedparameters. In some embodiments, the sensor for monitoring an acousticresponse may be configured to block frequencies returned that are equalto the inputted ultrasound frequencies. Put in another way, an acousticresponse monitored may be the acoustic response at frequencies otherthan the inputted ultrasound frequency.

In some embodiments, the baseline acoustic response may be measured byan acoustic/ultrasonic sensor (e.g., piezoelectric transducer or thelike) 402. A baseline acoustic response of the target tissue may bemeasured by delivering ultrasound toward the target tissue prior todelivery of the treatment fluid and measuring a reflected acousticsignal. In some embodiments, a harmonic response may be measured (e.g.,second, third, fourth harmonic or sub-harmonics, or the like) andrecorded. In some embodiments a broad band response may be measured andrecorded. In some embodiments, it may be preferable if the ultrasound isdelivered at a power and frequency that is used for subsequentlydispersing the fluid into the tissue after fluid delivery. In someembodiments, the baseline target tissue acoustic response will haveharmonics, but minimal sub harmonics and broad band responses.

After measuring the baseline acoustic response 402 from the targettissue and after fluid delivery into the tissue (e.g., via injection,infusion or the like) ultrasound may be applied to disperse the fluidinto the target tissue 403. During ultrasound application toward thetarget tissue to disperse the fluid into the tissue, an acousticresponse and changes in acoustic response may be monitored using theacoustic response sensor 404. In some embodiments, the acoustic responseof the tissue is monitored. In some embodiments, the acoustic responseof the fluid is monitored. In some embodiments, an acoustic response ofan interaction between the solution and the tissue is monitored. In someembodiments, combinations of the acoustic response of the tissue, thefluid, and/or the interaction between the fluid with the tissue aremonitored and recorded. Similar to the baseline acoustic responsemeasurement, in some embodiments, a harmonic response may be monitored(e.g., second, third, fourth harmonic or sub-harmonics, or the like)during fluid dispersal. In some embodiments, a broad band response maybe monitored during fluid dispersal. In some embodiments, the signalreceived is recorded at frequencies other than the applied frequency.For example, if a 1 MHz ultrasound is applied, the received of signal atfrequencies other than 1 MHz is recorded. The ultrasound delivery maythen be adjusted 406 based on changes in the recorded signal and/or bycomparing the recorded signal to the baseline measurement.

According to some embodiments, changes in the acoustic response of thetarget tissue, the fluid, and/or an interaction between the fluid andthe tissue during fluid dispersion into the tissue may be indicative ofa need to adjust an ultrasound delivery parameter. By monitoring forthese changes in acoustic response, a system may be configured to makeautomatic adjustments to the delivered ultrasound.

For example, in some embodiments, the power and frequency may begradually increased until a desired strength of harmonic, subharmonic,and/or broad band response is achieved. A subharmonic at ½ the inputfrequency may be measured and may be indicative of dispersion throughmicrostreaming and/or cavitation. In some embodiments higher harmonicstrengths may be of interest (e.g., 2f, 3f, out to 10f or the like) andmeasured by a spectrum analyzer. In some embodiments, broad bandresponse may be associated with cavitation events within the fluid ormicrostreaming of the fluid into the interstitial space. In someembodiments, the injected fluid may generate a subharmonic response inresponse to the delivered ultrasound that is not typically generated byhealthy tissue. Thus, a subharmonic response during delivery of theultrasound may be associated with an amount of fluid that has not yetbeen dispersed. Accordingly, a subharmonic response during ultrasounddelivery may be monitored and as the fluid is dispersed into the tissue,a subharmonic signal will go down. When the subharmonic signaldisappears or returns to within a threshold of the baseline tissueresponse, ultrasound delivery may be ceased, according to someembodiments.

Optionally, in some embodiments, the monitored acoustic response may becompared to the measured baseline acoustic response. Adjustments to theultrasound delivery may be based on a difference between the monitoredacoustic response and the measured baseline acoustic response. In someembodiments when the monitored acoustic response during fluid dispersionreturns to within a threshold of the measured baseline response, thesystem may adjust ultrasound delivery, for example by terminating theultrasound delivery. In some embodiments, a spectral analyzer may beused to identify a difference or similarity between the monitoredacoustic response and the baseline response. When the monitored acousticresponse returns to within the threshold range of the measured baselineacoustic response, the fluid delivered to the patient may besufficiently dispersed throughout the tissue.

If dispersal is insufficient, adjustments to power and frequency of theapplied ultrasound may be made. Additionally or alternatively, a partialpressure of gas in the injected fluid may be adjusted. In someembodiments, the partial pressure may be decreased such that a higherultrasound level may be used. Optionally, the partial pressure may beincreased to increase the amount of cavitation (and subharmonics andbroad band response). Accordingly, in some embodiments, the injectedfluid may act as an acoustic contrast agent due to the increase in gascontent and induced cavitation. The gas content of the injected fluidmay generate subharmonics not typically generated by tissue alone. Thus,as the fluid is dispersed into the tissue, a subharmonic signal willdissipate which will be indicative of a progress of the ultrasound drugdispersion procedure. For example, FIGS. 6A-6C show an exemplaryacoustic response of water under low, medium, and higher acoustic powers(with signal noise suppressed). FIG. 6A shows an acoustic response ofbulk water at low power—an input wave at about 1 MHz and higherharmonics at 2, 3 MHZ. The response which includes the input frequencyand its harmonics may be representative of a baseline acoustic responsefrom a tissue of a patient. Even at higher power levels such as tocreate an acoustic response illustrated FIG. 6B and FIG. 6C in bulkwater, a patient's baseline tissue response (without infused ordelivered fluid) will be qualitatively similar to the acoustic responseshown in FIG. 6A, but may have different values of the peaks of thelines. FIG. 6B illustrates an acoustic response of bulk water with apower that is five times greater than in FIG. 6A. Here the acousticresponse displaces cavitation in the broad band acoustic response andalso strong subharmonics which is a response at (f/2, approximately 500Hz). FIG. 6C illustrates an acoustic response of bulk water with a powerthat is five times greater than in FIG. 6B. Here, the subharmonic (f/2)and ultraharmonics (3f/2, 5f/2, etc.) are strong as is the broad bandnoise from internal cavitation. Various aspects of this spectrum withthese features may be expected when the ultrasound is applied to apatient after fluid has been injected. The difference between thespectrum in FIG. 6C and the baseline spectrum acquired at the sameacoustic power may be a measure of the progress of the ultrasonic drugdispersion. When dispersion is complete, the measured spectrum shouldreturn back toward the baseline which may have a form of the spectrumshown in FIG. 6A, but may have different values for the peaks. If thesound field power is not high enough, then the spectrum may be similarto that of FIG. 6A. Thus in some embodiments, traditional gas filledcapsules as contrast agents are not used and thus acoustic responses(harmonic, subharmonic, or broad band responses) from gas filledcapsules as contrast agents are not recorded and not used for monitoringdrug dispersal through tissue.

Monitoring for dispersion of fluid and therapeutic agents may beparticularly advantageous when treating cancerous tissue. Cancer tissuemay have tighter interstitial spaces that are more difficult topenetrate with the injected fluid. Accordingly, monitoring an acousticresponse of the target tissue, the injected fluid, and/or an interactionbetween the injected fluid and the target tissue may be advantageous formonitoring dispersion and making adjustments to ultrasound delivery whenthe fluid and therapeutic agent insufficiently disperse into the targettissue (e.g., cancer tissue, radiated tissue, or the like).

When the system adjusts ultrasound delivery, for example, by terminatingthe delivery of ultrasound, the system may output an alert according tosome embodiments 408. The alert may be indicative of an adjustment madeto the ultrasound delivery. The alert may be a visual alert, audioalert, and/or a haptic alert or combinations thereof. For example, thealert may be presented on a display of the system or output through oneor more light sources (e.g., red, yellow, green LEDs or the like) on theultrasound generator or the ultrasound applicator. Optionally, the alertmay include a continuous sound or a one or a series of discrete beeps.An audio alert may be a record voice in some embodiments. For example,an audio alert from the system may advise the user that dispersion ofthe fluid and therapeutic agent is sufficient or complete. Optionally,the alert may be a haptic vibration transmitted to the hand of the userof the system.

Methods of Using Systems

According to some embodiments, methods of using the systems describedabove are provided. A subject can be in need of delivery of at least onetherapeutic agent to at least one target tissue as described herein. Insome embodiments, the target tissue can have a low blood supply. In someembodiments, the target tissue comprises tissue of an extremity, forexample a leg, thing, knee, calf, foot, toe, arm, elbow, hand, finger,nose, ear, or the like. A system as described herein can be provided. Insome embodiments, the system comprises a solution comprising thetherapeutic agent in the container. In some embodiments, the operatorprepares or places a solution comprising the therapeutic agent in thecontainer. The operator can select a desired partial pressure of inertgas in the solution. In some embodiments, the operator applies a sourceof inert gas and/or a vacuum as described herein to increase or decreasethe partial pressure to the desired level. In some embodiments, thesolution is mixed or agitated as described herein to dissolve the inertgas in the solution. The operator can use the tissue interface of thesystem to apply the solution comprising a therapeutic agent to thetarget tissue directly, or to an area near the target tissue. Theoperator can then apply ultrasound energy to disperse the therapeuticagent in the target tissue. In some embodiments, the operator preselectsa desired amount of cavitation, for example, so that a desired amount ofdispersal in the target tissue can be achieved, thus achieving a desiredconcentration of therapeutic agent in the target tissue. In someembodiments, the system comprises a sensor, and automatically adjuststhe ultrasound energy and/or frequency, and/or rate of administration ofsolution comprising therapeutic agent in order to maintain a desiredlevel of cavitation. In some embodiments, therapeutic agent isadministered for a specified period of time at the desired level ofcavitation so as to achieve a desired concentration of therapeutic agentin the target tissue.

According to some embodiments, a method of delivering an antibiotic toan extremity of a subject is provided. The extremity can be otherwiseuntreatable by intravenous administration of antibiotic, for example dueto low blood flow in the extremity. A system as described above can beprovided. Inert gas can be applied to the solution while the solution ismixed or agitated, and/or a vacuum can be applied to the solution toarrive at a desired partial pressure of inert gas in the solution. Thetissue interface of the system can be applied at or near the site ofinfection, and solution comprising the antibiotic can be administered.Ultrasound energy can be applied transcutaneously, using the ultrasoundapplicator of the system at or near the site of infection. An effectiveconcentration of antibiotic can be delivered at or near the site ofinfection. In some embodiments, the sensor of the system detectsacoustic feedback from the subject, and ultrasound parameters (forexample power and/or frequency), and/or the rate of administration offluid comprising the therapeutic agent are adjusted automatically so asto achieve a desired level of cavitation in fluid in the subject. Insome embodiments, the extremity comprises a leg, thing, knee, calf,foot, toe, arm, elbow, hand, finger, nose, or ear. In some embodiments,the subject is diabetic. In some embodiments, the antibiotic comprises abeta-lactam antibiotic. In some embodiments, the antibiotic comprisesCefazolin. In some embodiments, the antibiotic comprises Vancomycin. Insome embodiments, the antibiotic comprises Cefazolin, and the devicecomprises Cefazolin at a concentration of at least about 4000 μg/ml insolution. In some embodiments, upon dispersal in the target tissue, theCefazolin is at a concentration of about 1000 μg/ml. In someembodiments, the system comprises a solution comprising the antibioticagent in the container. In some embodiments, the operator prepares orplaces a solution comprising the therapeutic agent in the container. Theoperator can select a desired partial pressure of inert gas in thesolution. In some embodiments, the operator applies a source of inertgas and/or a vacuum as described herein to increase or decrease thepartial pressure to the desired level. In some embodiments, the solutionis mixed or agitated as described herein to dissolve the inert gas inthe solution.

Example

An operator identifies a diabetic patient having an infection in a limbwith limited blood flow at the site of infection. The operator prepares100 cc of a saline solution comprising 1,000 μg/ml of Cefazolin andplaces it in the container of the system. The operator applies argon tothe container while the system mixes the solution in the container, soas to achieve a partial pressure of argon of about 20 kPa. The operatoradministers a tissue interface comprising a cannula directly above thesite of infection in the subject, and delivers the solution there. Theoperator uses the ultrasound applicator of the system to applyultrasound energy at 100 kHz and 2 watts/cm² at the site ofadministration. Solution comprising Cefazolin is dispersed in the targettissue. In response to acoustic feedback from a sensor on the ultrasoundapplicator, the frequency and power of ultrasound energy are adjusted.

General

With respect to the use of substantially any plural and/or singularterms herein, those having skill in the art can translate from theplural to the singular and/or from the singular to the plural as isappropriate to the context and/or application. The varioussingular/plural permutations may be expressly set forth herein for sakeof clarity. Headings are provided herein for organization purposes, anddo not limit the scope of application of embodiments herein.

It will be understood by those skilled in the art that, in general,terms used herein, and especially in the appended claims (e.g., bodiesof the appended claims) are generally intended as “open” terms (e.g.,the term “including” should be interpreted as “including but not limitedto,” the term “having” should be interpreted as “having at least,” theterm “includes” should be interpreted as “includes but is not limitedto,” etc.). It will be further understood by those within the art thatif a specific number of an introduced claim recitation is intended, suchan intent will be explicitly recited in the claim, and in the absence ofsuch recitation no such intent is present. For example, as an aid tounderstanding, the following appended claims may contain usage of theintroductory phrases “at least one” and “one or more” to introduce claimrecitations. However, the use of such phrases should not be construed toimply that the introduction of a claim recitation by the indefinitearticles “a” or “an” limits any particular claim containing suchintroduced claim recitation to embodiments containing only one suchrecitation, even when the same claim includes the introductory phrases“one or more” or “at least one” and indefinite articles such as “a” or“an” (e.g., “a” and/or “an” should be interpreted to mean “at least one”or “one or more”); the same holds true for the use of definite articlesused to introduce claim recitations. In addition, even if a specificnumber of an introduced claim recitation is explicitly recited, thoseskilled in the art will recognize that such recitation should beinterpreted to mean at least the recited number (e.g., the barerecitation of “two recitations,” without other modifiers, means at leasttwo recitations, or two or more recitations). Furthermore, in thoseinstances where a convention analogous to “at least one of A, B, and C,etc.” is used, in general such a construction is intended in the senseone having skill in the art would understand the convention (e.g., “asystem having at least one of A, B, and C” would include but not belimited to systems that have A alone, B alone, C alone, A and Btogether, A and C together, B and C together, and/or A, B, and Ctogether, etc.). In those instances where a convention analogous to “atleast one of A, B, or C, etc.” is used, in general such a constructionis intended in the sense one having skill in the art would understandthe convention (e.g., “a system having at least one of A, B, or C” wouldinclude but not be limited to systems that have A alone, B alone, Calone, A and B together, A and C together, B and C together, and/or A,B, and C together, etc.). It will be further understood by those withinthe art that virtually any disjunctive word and/or phrase presenting twoor more alternative terms, whether in the description, claims, ordrawings, should be understood to contemplate the possibilities ofincluding one of the terms, either of the terms, or both terms. Forexample, the phrase “A or B” will be understood to include thepossibilities of “A” or “B” or “A and B.”

In addition, where features or aspects of the disclosure are describedin terms of Markush groups, those skilled in the art will recognize thatthe disclosure is also thereby described in terms of any individualmember or subgroup of members of the Markush group.

As will be understood by one skilled in the art, for any and allpurposes, such as in terms of providing a written description, allranges disclosed herein also encompass any and all possible sub-rangesand combinations of sub-ranges thereof. Any listed range can be easilyrecognized as sufficiently describing and enabling the same range beingbroken down into at least equal halves, thirds, quarters, fifths,tenths, etc. As a non-limiting example, each range discussed herein canbe readily broken down into a lower third, middle third and upper third,etc. As will also be understood by one skilled in the art all languagesuch as “up to,” “at least,” “greater than,” “less than,” and the likeinclude the number recited and refer to ranges which can be subsequentlybroken down into sub-ranges as discussed above. Finally, as will beunderstood by one skilled in the art, a range includes each individualmember. Thus, for example, a group having 1-3 articles refers to groupshaving 1, 2, or 3 articles. Similarly, a group having 1-5 articlesrefers to groups having 1, 2, 3, 4, or 5 articles, and so forth.

While various aspects and embodiments have been disclosed herein, otheraspects and embodiments will be apparent to those skilled in the art.The various aspects and embodiments disclosed herein are for purposes ofillustration and are not intended to be limiting, with the true scopeand spirit being indicated by the following claims.

While the present invention has been described in some detail forpurposes of clarity and understanding, one skilled in the art willappreciate that various changes in form and detail can be made withoutdeparting from the true scope of the invention.

The term “comprising” as used herein is synonymous with “including,”“containing,” or “characterized by,” and is inclusive or open-ended anddoes not exclude additional, unrecited elements or method steps.

All numbers expressing quantities of ingredients, reaction conditions,and so forth used in the specification are to be understood as beingmodified in all instances by the term “about.” Accordingly, unlessindicated to the contrary, the numerical parameters set forth herein areapproximations that may vary depending upon the desired propertiessought to be obtained. At the very least, and not as an attempt to limitthe application of the doctrine of equivalents to the scope of anyclaims in any application claiming priority to the present application,each numerical parameter should be construed in light of the number ofsignificant digits and ordinary rounding approaches.

The above description discloses several methods and materials of thepresent invention. This invention is susceptible to modifications in themethods and materials, as well as alterations in the fabrication methodsand equipment. Such modifications will become apparent to those skilledin the art from a consideration of this disclosure or practice of theinvention disclosed herein. Consequently, it is not intended that thisinvention be limited to the specific embodiments disclosed herein, butthat it cover all modifications and alternatives coming within the truescope and spirit of the invention.

The foregoing description and Examples detail certain embodiments. Itwill be appreciated, however, that no matter how detailed the foregoingmay appear in text, the invention may be practiced in many ways and theinvention should be construed in accordance with the appended claims andany equivalents thereof.

What is claimed is:
 1. A system for ultrasonic delivery of a therapeuticagent, the system comprising: an ultrasound transducer configured todeliver ultrasound energy toward an injected solution with thetherapeutic agent dissolved therein to disperse the therapeutic agentinto interstitial space of the target tissue; a sensor configured tomonitor an acoustic response of the target tissue generated in responseto ultrasound delivered by the ultrasound transducer; a controllercoupled with the sensor and the ultrasound transducer, the controllerconfigured to monitor the dispersal of the injected solution with thetherapeutic agent dissolved therein based on the acoustic response ofthe target tissue monitored by the sensor and further configured toadjust the ultrasound delivery depending on the monitored acousticresponse of the target tissue, wherein the sensor is further configuredto measure a baseline acoustic response from the target tissue, andwherein the controller is configured to identify an end point for theultrasound delivery by comparing the monitored acoustic response of thetarget tissue to the measured baseline acoustic response of the targettissue.
 2. The system of claim 1, wherein the controller identifies theend point for the ultrasound delivery when the monitored acousticresponse of the target tissue returns to within a predeterminedthreshold of the measured baseline acoustic response of the targettissue.
 3. The system of claim 1, wherein the controller is furtherconfigured to adjust the ultrasound delivery by automatically ceasingdelivery of the ultrasound by the ultrasound transducer when thecontroller identifies an end point for the ultrasound delivery.
 4. Thesystem of claim 1, wherein the controller is further configured tooutput a user alert to signal adjustments to the ultrasound delivery,wherein the user alert is associated with an end point of the ultrasounddelivery.
 5. The system of claim 1, wherein the sensor is configured tomonitor a harmonic, subharmonic, and/or broad band response of thetarget tissue generated in response to the applied ultrasound.
 6. Thesystem of claim 5, wherein the sensor is configured to monitor aharmonic, subharmonic, and/or broad band response of the injectedsolution generated in response to the applied ultrasound.
 7. The systemof claim 5, wherein the sensor is configured to monitor a harmonic,subharmonic, and/broad band response of an interaction between theinjected solution and the target tissue generated in response to theapplied ultrasound.
 8. The system of claim 1, wherein the controller isfurther configured to apply a Fast Fourier Transform to the monitoredacoustic response of the target tissue to the applied ultrasound.
 9. Thesystem of claim 1, wherein the ultrasound transducer is configured todeliver ultrasound at an applied frequency and wherein the sensor isconfigured to monitor target tissue acoustic responses at frequenciesother than the applied frequency, wherein the sensor is configured tomonitor a second harmonic response of the target tissue.
 10. The systemof claim 1, wherein the sensor is configured to monitor an acousticresponse of the injected solution generated in response to the appliedultrasound, and wherein a majority of the acoustic response of theinjected solution is due to a concentration of dissolved gas within theinjected solution.
 11. The system of claim 1, wherein the controlleradjusts the ultrasound delivery without using an acoustic response ofinjected gas filled drug carriers and without using an acoustic responseof contrast agent that is made of gas filled capsules.
 12. The system ofclaim 1, further comprising a user input, the user input configured toreceive a user inputted volume of injected solution, a user inputteddepth of target tissue, and/or a user inputted area of target tissue.13. The system of claim 1, further comprising a temperature sensorcoupled with the ultrasound transducer to monitor a temperature of aface of the ultrasound transducer, and wherein the controller is coupledwith the temperature sensor and configured to prevent or ceaseultrasound delivery when the temperature of the face of the ultrasoundtransducer exceeds a safety threshold and further configured to output atemperature safety warning in a manner perceptible to the user.
 14. Amethod of monitoring a level of dispersal of a therapeutic agent into atarget tissue, the method comprising: energizing an ultrasoundtransducer to deliver ultrasound energy toward a bolus of injectedsolution including the therapeutic agent dissolved therein to dispersethe bolus of injected solution with the therapeutic agent intointerstitial space of the target tissue; monitoring the dispersal of thebolus of injected solution with the therapeutic agent into theinterstitial space of the target tissue by monitoring an acousticresponse of the target tissue or the injected solution to the appliedultrasound during the ultrasound application; adjusting the ultrasounddelivery based on the monitored acoustic response of the target tissueor the injected solution to the applied ultrasound.
 15. The method ofclaim 14, further comprising measuring a baseline acoustic response fromthe target tissue, wherein the baseline acoustic response of the targettissue is associated with the acoustic response of the target tissueprior to injection of the solution and identifying an end point for theultrasound delivery by comparing the monitored acoustic response of thetarget tissue to the measured baseline acoustic response of the targettissue, wherein comparing the monitored acoustic response of the targettissue to the measured baseline acoustic response of the target tissuecomprises determining when the monitored acoustic response of the targettissue returns to within a predetermined threshold of the measuredbaseline acoustic response of the target tissue.
 16. The method of claim14, wherein monitoring the acoustic response of the target tissue or theinjected solution comprises monitoring a harmonic, subharmonic, and/orbroad band response of the target tissue or the injected solution to theapplied ultrasound, and further comprising monitoring a harmonic,subharmonic, and/or broad band response of an interaction between theinjected solution and the target tissue.
 17. The method of claim 14,further comprising applying a Fast Fourier Transform to the monitoredacoustic response of the target tissue or the injected solution to theapplied ultrasound.
 18. The method of claim 14, wherein the ultrasoundtransducer delivers ultrasound at an applied frequency and whereinmonitoring the acoustic response of the target tissue comprisesmonitoring target tissue acoustic responses at frequencies other thanthe applied frequency, wherein a second harmonic response from thetarget tissue or the injected solution is monitored.
 19. The method ofclaim 14, wherein an end point of the ultrasound delivery is identifiedwithout using an acoustic response of injected gas filled drug carriers.20. The method of claim 14, further comprising monitoring a temperatureof a face of the ultrasound transducer, and preventing or ceasingultrasound delivery when the temperature of the face of the ultrasoundtransducer exceeds a safety threshold and outputting a temperaturesafety warning in a manner perceptible to the user.